Differentiation and activation phenotypes of lung T lymphocytes differ from those of circulating T lymphocytes.

We used dual laser two-color flow cytometry to compare the expression of surface markers associated with activation and with differentiation in lung and peripheral blood T lymphocytes from normal subjects. T cell subsets, defined based on their reactivity with monoclonal antibodies (MAb) OKT3, OKT4, and OKT8, were analyzed for expression of activation antigens as detected by MAbs to the interleukin-2 receptor, the transferrin receptor, and HLA-DR determinants. Whereas circulating T lymphocytes expressed the three activation antigens at low levels, and the total of T4+ and T8+ cells always approximated the number of T3+ cells, lung T lymphocytes of the T3+, T4+, and T8+ populations expressed the activation antigens at variable levels in combinations not seen in circulating lymphocytes, and the sum of T4+ and T8+ cells always exceeded the T3+ total. A proportion of T4+T8+ cells was detected in lung lymphocytes.     

Distribution of marker-specific lymphocyte subsets in healthy human subjects

Cell membrane surface markers on peripheral blood lymphocytes of healthy human subjects were analysed by flow cytometry using monoclonal antibodies. Peripheral blood was obtained from 156 healthy individuals of both sexes, and ages ranging from 2-82 yr. The distribution of the lymphocytes with specific cell markers according to differences in sex and age was calculated. There was a significant difference (p less than 0.05) between sexes in the mean percentages of OKT4+ and OKT8+ cells and in the OKT4/8 ratio while the OKT3+, OKT10+ and OKIa1+ cells, and OKT4/8 ratio clearly correlated with age. A significant correlation among OKT3+, OKT4+, OKT8+, OKT11+ and OKIa1+ cells was obtained, and the results indicated that the percentage of a specific marker-positive cell varied under the influence of other marker-positive cells.     

Surface markers of peripheral blood lymphocytes in Vogt-Koyanagi-Harada disease

The cell membrane markers on peripheral blood lymphocytes of 10 patients with Vogt-Koyanagi-Harada disease (VKH) were analyzed by laser flow cytometry using monoclonal antibodies. Seven patients with active uveitis and 98 normal control subjects were also studied. The percentage of OKT3+, OKT4+ and OKT11+ cells were significantly lower while OKIa1+ cell were higher in VKH compared to controls. The percentage of cells reacting with monoclonal antibodies were slightly affected during steroid therapy, but returned to the pretreatment level after cessation of the therapy. OKIa1+ cells were shown to be increased in active uveitis while percentages of cells with other cell markers remained unchanged when the results were compared with that of the control. The findings suggest that the analysis of cell membrane markers on lymphocytes in VKH could be a significant parameter in clinical medicine.     

Immune cell populations in cutaneous delayed-type hypersensitivity

Delayed-type hypersensitivity (DTH) is a prototypic T lymphocyte- mediated response to antigenic challenge. In this study, mononuclear cells infiltrating the skin during cutaneous response to tuberculin in presensitized human subjects (responders) and nonimmune controls were identified using monoclonal antibodies by indirect immunofluorescence. In both responders and controls the infiltrate consisted mainly of T lymphocytes (T11+ and OKT3+) and monocytes (OKM1+, 63D3+, Mo2+) which initially accumulated in proximity to small blood vessels and later infiltrated the interstitial dermis and epidermis. More T lymphocytes reacted with OKT4 than with OKT8. 6 h after tuberculin the ratio of OKT4/OKT8 in tissue from responders exceeded that in blood, whereas in tissues studied at 15-48 h and in all control tissues those ratios in blood and tissue were similar. Evidence of T lymphocyte activation was sought using monoclonal antibodies anti-Tac, OKT9, and OKT10. In responders but not in controls the proportion of infiltrating cells reactive with these antibodies increased during the course of DTH. The presence of activated T lymphocytes in tissue was not associated with a comparable increase in peripheral blood cell populations identified by anti-Tac and OKT10. Studies using anti-B1, Leu-7, and anti-IgD/IgM revealed comparatively few reactive cells. Dual-labeling studies demonstrated that most Leu-7--reactive cells also bound T11 while fewer bound OKM1 or OKT8 and that cells reactive with OKIa1 and T11 constituted largely nonoverlapping populations. Specific patterns of reactivity were not observed when tissues were stained with anti-human C3, or poly C9-MA, a monoclonal antibody reactive with a neoantigen on polymerized C9 of the membrane attack complex of complement. The number of epidermal Langerhans cells identified by OKT6 was similar in responders and controls. Thus, the cutaneous response to tuberculin in sensitized individuals is characterized by early enrichment of the OKT4 subpopulation of T lymphocytes in tissue infiltrates and subsequent (15- 48 h) evidence of T lymphocyte activation.     

Correction of interleukin-2 production in patients with systemic lupus erythematosus by removal of spontaneously activated suppressor cells.

Interleukin-2 (IL-2) production in vitro is depressed in systemic lupus erythematosus (SLE) patients. It is not known whether this abnormality is caused by a defect in the producer lymphocytes or by excessive suppression. We report that removal of OKT8 (Leu 2a)+ cells increased the IL-2 production by in vitro-stimulated lymphocytes to normal or above normal levels in 19 of 21 SLE patients. This increase was more apparent in those patients with clinically inactive disease and/or receiving less than 7.5 mg of prednisone. Removal of OKT8+ cells from normals did not significantly increase IL-2 activity. SLE, but not normal, OKT8+ cells decreased IL-2 production when added back to autologous OKT8-depleted cells. In some experiments, OKT8+ cells from normal donors also suppressed IL-2 production in SLE. This result suggests that the defect in IL-2 production is complex and may involve multiple cell interactions. Three lines of evidence suggest that the SLE OKT8+ cells actively inhibit the production of IL-2 rather than passively absorb this lymphokine: (a) only 3.2% of SLE lymphocytes expressed IL-2 receptors as detected with anti-Tac; (b) freshly prepared SLE lymphocytes did not absorb IL-2; and (c) cell-free supernatants from SLE OKT8+ cells inhibited IL-2 production, but not IL-2 activity. Double-labeling studies by flow cytometry revealed that 19.3% of SLE OKT8+ cells were also Ia-positive, and approximately 33% co-expressed the natural killer cell marker, HNK-1 (Leu 7). Removal of Leu 7+ cells also significantly elevated IL-2 production in SLE. These studies suggest that one or more circulating mononuclear cell subsets in SLE patients can suppress IL-2 production and that one subset may possibly belong to a non-T, non-B "third mononuclear population."     

Lymphoid leukemia and non-Hodgkin's lymphoma type continuum, superimposed to lymphocyte differentiation step continuum. A proposition for a revised W. H. O. lympiioid leukemia-lymphoma categorisation

We have classified 200 cases of lymphoid leukemia and non-Hodgkin lymphoma (LL and L) typed with as many monoclonal antibodies as possible for each case in the WHO Leukemia and Lymphoma categorisation modified according to the today knowledge of normal cell differentiation. We have found that the lymphoid acute leukemias correspond respectively to normal differentiation steps: the [microblastic] to the polyvalent stem cell TdT+, Ia+, B4- or to the lymphoid progenitor TdT+, Ia+, B4-; the [prolymphoblastic T] to the prothymocyte TdT+, OKT11+, OKT10+, 9+, 6-, 4-, 8-; the [prolymphoblastic non T] to the B precursor B4+, B1+, J5+, C mu-, sIg-; the [T-macrolymphoblastic] to the OKT6+ thymocyte; the [B-macrolymphoblastic] to the large pre-B C mu+; the [prolymphocytic T] to the OKT6-, 3+, 4+ and 8+ thymocyte; the [prolymphocytic B] to the small pre-B C mu+; the Burkitt's leukemia to a pre-B cell transformed into a lymphoblastoid cell sIg mu. The B-CLL is constituted of sIg mu+, gamma-, Ia+, B4+, B1+, FC+ virgin lymphocytes and the T-cell either of OKT3+, 4+ or of 8+ peripheral T-lymphocyte, the mantle zone B- lymphoma is constituted of sIg mu+, FC- primary lymphocytes. The B-centro-follicular lymphomas are made of sIg mu+, delta+, gamma+ either small cell cleaved, or large cell. The Burkitt's and non-endemic Burkitt's lymphomas are made of transformed cells into sIg mu+ lymphoblastoid B-cells. We have described a non-blastic, non-Burkitt's, non-follicular, medium cell lymphoma sIg+. The B-immunoblastic lymphoma is sIg mu+, delta-, gamma+, FC+.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ecto-5′-Nucleotidase Activity in Human T Cell Subsets. DECREASED NUMBERS OF ECTO-5′-NUCLEOTIDASE POSITIVE CELLS FROM BOTH OKT4+ AND OKT8+ CELLS IN PATIENTS WITH HYPOGAMMAGLOBULINEMIA

T lymphocytes from control subjects were separated into subsets using monoclonal antibodies of the OKT series and complement lysis and analyzed for ecto-5'-nucleotidase activity both by quantitative radiochemical assay and a histochemical stain. T cells from 15 control subjects contained 54+/-4% OKT4(+) (helper/inducer) cells and 32+/-3% OKT8(+) (cytotoxic/suppressor) cells. Total T cell ecto-5'-nucleotidase activity was 10.9+/-2.1 nmol/h per 10(6) cells with 25+/-7% positive by histochemical stain. Ecto-5'-nucleotidase activity in OKT4-enriched populations was 5.43+/-1.8 nmol/h per 10(6) cells with 14+/-2% positive by histochemical stain; that in OKT8-enriched populations was 17.1+/-5.9 nmol/h per 10(6) cells with 35+/-8% positive by histochemical stain.Two of four patients with congenital agammaglobulinemia and four of seven patients with common variable immunodeficiency had decreased proportions of OKT4(+) T cells with corresponding increases in the proportions of OKT8(+) T cells (OKT4/OKT8 = 0.60 to 1.0 as compared with 1.7+/-0.2 for control subjects). All four patients with congenital agammaglobulinemia, and three of seven patients with common variable immunodeficiency also had low T cell ecto-5'-nucleotidase activity (<5.5 nmol/h per 10(6) cells). Ecto-5'-nucleotidase activity in OKT4- enriched populations isolated from four patients with low total T cell activity was 2.85+/-0.90 nmol/h per 10(6) cells with 10+/-4% positive by histochemical stain; that in OKT8-enriched populations was 6.82+/-1.7 nmol/h per 10(6) cells with 7.5+/-3% positive by histochemical stain. Thus, the number of ecto-5'-nucleotidase positive cells is decreased, especially in the OKT8(+) subpopulation, and the low total T cell ecto-5'-nucleotidase activity seen in these patients is due to fewer positive cells rather than to substantially less activity per cell.Our data indicate that ecto-5'-nucleotidase activity defines two subpopulations of T lymphocytes (ecto-5'-nucleotidase positive and negative), the proportions of which are markedly altered in many patients with hypogammaglobulinemia. In preliminary studies with seven patients, increased numbers of ecto-5'-nucleotidase negative T cells appeared to correlate with increased suppressor T cell activity toward in vitro immunoglobulin synthesis. Therefore, ecto-5'-nucleotidase may be a useful cell surface marker in the study of imbalances of regulatory T cell subsets in patients with antibody synthesis disorders.     

HLA-DR human histocompatibility leukocyte antigens-restricted lymphocyte-monocyte interactions in the release from monocytes of acidic isoferritins that suppress hematopoietic progenitor cells

Acidic isoferritins, which under normal conditions are released from monocytes and macrophages, have a suppressive effect in vitro on granulocyte-macrophage, erythroid, and multipotential hematopoietic progenitor cells. Cell interactions modulating the release of acidic isoferritin-inhibitory activity (AIFIA) from human monocytes were investigated using the bone marrow granulocyte-macrophage progenitor cells as a target cell assay for assessing AIFIA. Monocytes, in the absence of T lymphocytes, released AIFIA when allowed to condition culture medium at 10(4) or higher concentrations of monocytes/ml. However, subpopulations of T lymphocytes modulated the release of AIFIA from monocytes. OKT8+- and OKT4+-T lymphocytes were obtained from E-rosette-positive lymphocytes by using T lymphocyte subset-specific monoclonal antibodies in either a complement-dependent cytotoxicity test to select negatively for the cells or by selection using a "panning" procedure. OKT8+-T lymphocytes suppressed completely and OKT4+-T lymphocytes enhanced the constitutive release of AIFIA from monocytes. OKT4+ lymphocytes also induced the release of AIFIA from concentrations of 10(3) monocytes/ml which did not release measurable amounts of AIFIA by themselves. The release of AIFIA from monocytes involved HLA-DR+-monocytes and -T lymphocytes. Pulsing monocytes with monoclonal antibodies to framework determinants on HLA-DR molecules, in the absence of complement, did not influence the constitutive release of AIFIA. Pulsing monocytes or T lymphocyte subpopulations with such antibodies, in the absence of complement, blocked the suppressing and inducing activities of the appropriate subpopulations of T lymphocytes. Monoclonal antibodies to common determinants shared by HLA-A, B, and C molecules did not block these cellular interactions. Treating monocytes and T lymphocytes in a complement-dependent cytotoxicity test with dilutions of the anti-HLA-DR antibodies that did not block the cellular interactions removed the populations of monocytes constitutively releasing AIFIA and the T lymphocyte subsets modulating this release. Modulation of the release of AIFIA from monocytes by T lymphocyte subpopulations required the use of autologous cells, cells from HLA-identical siblings, or unrelated donors matched for HLA-DR. Matching for only one HLA haplotype gave partial responses and this was seen in testing cells from related individuals as well as among unrelated test combinations. These cellular interactions were not detected with HLA-DR-incompatible cells differing for two HLA-DR antigens. Admixture of such HLA-DR- incompatible allogeneic cells did not interfere with the regulation of AIFIA release in the autologous cell interactions. Thus, release of AIFIA from monocytes is restricted genetically by HLA-DR at the level of T lymphocyte-monocyte interactions. The genetic determinants on the HLA-class II molecules that induce stimulation in vitro in mixed lymphocyte culture (i.e., HLA-D), however, were not involved in this effort.     

Effects of glycyrrhizin (SNMC: stronger Neo-Minophagen C) in hemophilia patients with HIV infection

Glycyrrhizin (GL) not only has an inhibitory effect on HIV replication but also exhibits interferon-inducing and natural killer (NK)-enhancing effects and improves liver dysfunction. Thus, large doses of GL (200-800 mg/day) were intravenously administered for more than 8 weeks to 9 hemophilia A patients with HIV infection (asymptomatic carrier, AC). Lymphocyte count increased in all 9 cases. OKT4 OKT8 ratio was elevated in 6 out of the 9 cases and OKT4-positive lymphocytes increased in 8 out of the 9 cases; 66.7% and 88.9% improvement, respectively. Changes in NK cell activity and mitogenic responsiveness to PHA, Con A and PWM were not significant. Liver dysfunction, noted in 4 cases, clearly improved. Serum electrolytes, protein, lipids, and renal function were within normal levels and no serious side-effects were observed during treatment. On the other hand, in 3 cases of hemophilia without HIV infection, the number of OKT4 lymphocytes was not significantly altered during treatment. From these results, large dose administration of GL to HIV-positive hemophilia patients (AC) seems to be effective in preventing development of AC into AIDS by raising the number of decreased OKT4 lymphocytes and improving liver dysfunction.     

Alterations in lymphocyte subsets and serum immunoglobulin levels in patients with silicosis

The numbers of total lymphocyte and lymphocyte subsets in peripheral blood of patients with silicosis and their serum immunoglobulin (Ig) levels were studied to evaluate their immune status. The numbers of total lymphocytes and OKT4+ and OKT8+ cells tended to be decreased and the numbers of OKT3+ cells was significantly decreased (p less than 0.001), but that of OKIa-1+ cells was increased (p less than 0.001) in the patients. In the lymph nodes of the lung hilus, the ratio of OKT4+ cells to total lymphocytes was increased but that of OKT8+ cells to total lymphocytes was decreased. The serum levels of IgG and IgA were elevated in the patients with reduction in the numbers of total lymphocytes and OKT4+ cells in peripheral blood. The serum IgE levels in 17 of 82 patients were above 400 IU/ml. In 8 patients with serum IgE 82 patients were above 400 IU/ml. In 8 patients with serum IgE levels of more than 1,000 IU/ml, the numbers of total lymphocytes and OKT3+ and OKT4+ cells were decreased compared with those in controls. The following suggestions are proposed from the results: Increase and activation of helper T cells may be caused by the presentation of silica dust to macrophages in the lymph nodes, and these cells may then stimulate B cell proliferation and Ig production by B cells, resulting in increase in the serum Ig (IgG, IgA and IgE) level. Reduction in the number of OKT4+ cells helper/inducer T cells) in peripheral blood may be due to migration of helper T cells into the lymph nodes. These immunological events in patients with silicosis are probably due to the adjuvant effect of silica dust.     

Immunoelectron microscopic study of the distribution of T cell subsets in rheumatoid synovium

The perivascular mononuclear cell collections of the rheumatoid synovium were examined both at the light and electron microscopic level by an immunoperoxidase staining technique using monoclonal antibodies directed against T cell subsets. These accumulations were variable in composition and size, not only in specimens from different patients but in the same specimen. Some areas (lymphocyte-rich areas) contained mainly small lymphocytes in clusters and others (transitional areas) contained blast cells, macrophages, and plasma cells in addition to lymphocytes. The percentage of T4 staining cells correlated positively and the percentage of T8 staining cells correlated negatively with the percentage of lymphocytes in any given area. In contrast, the percentage of T4 cells correlated negatively and the percentage of T8 cells correlated positively with the percentage of macrophage-like cells in these areas. Approximately 80% of the total lymphocytes, both in the lymphocyte-rich areas and transitional areas, were T lymphocytes (OKT3 staining). In lymphocyte-rich areas, helper/inducer T lymphocytes (OKT4 staining) were predominent over suppressor/cytotoxic lymphocytes (OKT8 staining), and in such areas the mean T4:T8 ratio was 2.9. Macrophage-like cells were seen only in small numbers in this type of area. In the transitional areas, suppressor/cytotoxic lymphocytes (OKT8 staining) predominated over helper/inducer lymphocytes (OKT4 staining). In such areas the mean T4:T8 ratio was 0.8. The T8 cells in the transitional areas tended to be large in size and often had a blastic appearance, and the abundant macrophage-like cells infiltrating these areas were frequently in close contact with T8 lymphocytes. These findings indicate that the ratio of T4 to T8 lymphocytes in rheumatoid synovium varies with the type of area examined. In lymphocyte-rich collections, made up largely of quiescent small lymphocytes, T4 cells are predominant. In areas of apparent immunological reactivity, T8 cells are predominant. It is suggested that T8 cells proliferate in immunologically active areas of the synovium as a result of local stimulation of a T cell-mediated immune response.     

Absence of OKT4 antigen epitope: report of a case in a Brazilian population

During the study of 162 normal subjects we found an 8 month-old black girl without previous illnesses, especially infections, whose lymphocytes did not react with OKT4 monoclonal antibody. However the CD4 subset was present, since the number of lymphocytes which reacted with Leu 3a and T4 was normal. In addition the percentage of Fc mu+ lymphocytes, K cell activity and PHA response were normal. The proportion of the other lymphocyte subsets did not differ from normal controls. Four first degree relatives of this child had a normal proportion of OKT4+ lymphocytes. The absence of OKT4 epitope was previously reported as a rare genetic variant which was detected only in Japanese and in subjects of black African ancestry.     

Immune function during ageing in man: relation between serological abnormalities and cellular immune status

In a group of 176 apparently healthy aged people living at home (age range 62-86 years) the prevalences of monoclonal immunoglobulin and of autoantibodies did not differ from those found in other studies, but remarkably 38% of the people studied had cold lymphocytotoxic antibodies. The occurrence of serological abnormalities showed no age dependency. The participants were grouped according to serological abnormalities. The various groups showed no differences in peripheral blood mononuclear cell composition (concentration of B lymphocytes and T lymphocytes or of T lymphocyte subsets with OKT 4 and OKT 8 phenotype) or function (lymphocyte stimulation with phytohaemagglutinin, concanavalin A, pokeweed mitogen and antigen cocktail). Compared with a control group of young blood donors, the lymphocyte stimulation responses tended to be lower in the old age groups. It is concluded that, as measured in this study, humoral abnormalities during ageing are not associated with changes in B and T lymphocyte subsets or function.     

Impaired cell-mediated immunity in hemophilia. II. Persistence of subclinical immunodeficiency and enhancement of natural killer activity by lymphokines

We performed follow-up studies in 11 patients with asymptomatic classic hemophilia, who on initial study 8 to 12 months previously had demonstrated abnormalities of lymphocyte phenotype and function. Although all subjects remained well, diminished lymphocyte proliferative responses, natural killer activity, and decreased ratios of OKT4 helper/OKT8 suppressor lymphocytes persisted. Moreover, the absolute number of OKT4 helper lymphocytes fell in the patients from a mean of 745 +/- 73/microliter in the first study to 585 +/- 50/microliter in the follow-up study, which was lower than the control value of 857 +/- 87 (P less than 0.02). Despite diminished natural killer activity, patients with hemophilia had at least normal numbers of natural killer cells as determined by the presence of the OKM1 antigens and Giemsa staining to identify large granular lymphocytes. Patients with hemophilia had more Leu 11a-positive cells than controls. Lymphocyte binding to tumor targets was not diminished, and removal of adherent cells did not increase patients' natural killer activity to control levels. Incubation of patients' lymphocytes with alpha-interferon, gamma-interferon, or interleukin-2 resulted in enhancement of natural killer activity but did not reach control levels. Thus the diminished natural killer activity in patients with hemophilia retained responsiveness to lymphokines and was caused either by an intrinsic or acquired defect in the natural killer cell or by modulation by a nonadherent cell. Subclinical immunodeficiency in patients with hemophilia is not transient and is associated with a diminished number of OKT4 helper cells, a finding often associated with clinical immunodeficiency.     

Cell surface antigen expression in cultured lymphocytes derived from healthy HTLV-I carriers

We studied cell surface antigens on fresh and cultured peripheral blood lymphocytes (PBL) of healthy HTLV-I carriers. OKT4, OKT8 and OKIa1-positive cells were found to be within the normal range as compared with controls both in fresh and in cultured PBL. The percentage of Tac positive cells in HTLV-I carriers was shown to be higher in fresh PBL than that of controls. Furthermore the value increased significantly during cell culture in vitro and large blastoid cells appeared. The results suggested that HTLV-I proliferation in infected lymphocytes is activated in a serum-free environment and that small resting lymphocytes are transformed into Tac-positive large blastoid cells.     

Study of lymphocyte subpopulations and the expression of activation markers in diabetes mellitus types 1 and 2

Diabetic patients with the disease duration less than 1 year (group 1 eight patients with diabetes mellitus type I and group 2 seven patients with diabetes mellitus type II) and 8 healthy donors were examined for subpopulations of lymphocytes (CD 3-, CD 4-, CD 8-, CD 20-positive cells, CD4/CD8), expression of activation markers on peripheral blood mononuclears investigated with monoclonal antibodies of BMA and OKT series, and serum neopterin concentration. Group I patients had low CD4/CD8 and increased number of CD 8 cells, 1a/DR-positive lymphocytes (28.6 +/- 7%), OKT9-positive lymphocytes (8.0 +/- 4.7%), activated neopterin synthesis registered neither in group 2 patients nor donors. The number of CD 3 and CD 4 cells was similar in the diabetics and donors. B-lymphocyte level in group 1 patients was on the decrease. Unbalance in lymphocyte subpopulations, increased expression of activation markers and of serum neopterin can be noted in viral infection reflecting impairment of immunoregulating mechanisms in diabetes mellitus type I.     

Laboratory monitoring of therapy with OKT3 and other murine monoclonal antibodies

The first monoclonal antibody (MAb) approved by the Food and Drug Administration (FDA) for therapeutic use, OKT3, is now a standard treatment for organ allograft rejection. This article reviews the interpretation of laboratory tests used to manage patients treated with MAb. Emphasis is placed on OKT3, with which the experience is also the greatest, although comparisons with other MAbs in clinical trials is also discussed.     

The lymphocyte subpopulations involved in cytotoxicity generated by co-culture with autologous and allogeneic Epstein-Barr virus-transformed cell line

When peripheral blood lymphocytes from healthy adults are cultured with autologous (auto) or allogeneic (allo) Epstein-Barr virus-transformed cells (LCL), non-specific killer activity against NK-sensitive K562 and NK-resistant Raji, as well as specific killer activity against LCL is enhanced or generated. We analyzed the cell subsets possessing such cytotoxicity using monoclonal antibodies (MoAb). OKT3, a MoAb to T cell receptor-associated molecule, added in the effector phase suppressed the killer activity against LCL but not against Raji or K562. In contrast, OKT3 added in the induction phase abolished the generation of cytotoxicity against all targets. The addition of OKT8 in either the effector or induction phase inhibited anti-LCL killing induced by stimulation with alloLCL. This suggests that CD8 is required for recognition of alloLCL. The treatment of effector cells with MoAb and complement(C) revealed that killers against LCL were OKT8+ Leu11-, and those against K562 were OKT8- Leu11+. When auto-LCL were used as stimulator, removal of OKT4+ cells in the induction phase diminished the cytotoxicity against all targets, indicating that CD4+ T cells recognize autoLCL. Elimination of CD8+ cells from responder did not decrease the generation of killer activity. Further experiments suggested that this was caused by the coexistence of CD4+ killer cells or by the increase of residual CD8+ effector cells.     

CD4-mediated stimulation of human eosinophils: lymphocyte chemoattractant factor and other CD4-binding ligands elicit eosinophil migration

Lymphocyte chemoattractant factor (LCF) is a tetrameric glycoprotein of 56,000 relative molecular mass produced by activated T lymphocytes. LCF binds to CD4 and has previously been found to stimulate migration of CD4+ lymphocytes and monocytes. Because human eosinophils, like T cells and monocytes, express CD4, we examined functional responses of eosinophils to LCF. Recombinant LCF (rLCF) expressed in COS cells was purified on a CD4 affinity column. Migration of eosinophils was elicited by rLCF at low concentrations: the 50% effective dose (ED50) was 10(-12) to 10(-11) M, concentrations 100- to 1,000-fold lower than the ED50s for the recognized eosinophil chemoattractants C5a and platelet-activating factor. Two other ligands which bound to CD4, human immunodeficiency virus-1 envelope glycoprotein gp120 and monoclonal antibody OKT4, also stimulated eosinophil migration. Monovalent OKT4 Fab competitively inhibited eosinophil responses to rLCF. rLCF did not influence other functional responses of eosinophils tested, including degranulation, superoxide generation, leukotriene C4 production, in vitro survival, or surface expression of the adherence receptor CR3 (CD11b), human histocompatibility leukocyte antigen DR, or interleukin 2 receptor p55 (CD25). We conclude that CD4 on eosinophils is capable of transducing a migratory stimulus and serves as a receptor for a chemoattractant lymphokine LCF. T cell-derived LCF may contribute to recruitment of eosinophils and CD4+ mononuclear cells concomitantly at inflammatory reactions.     

Temporal interrelationships between circadian rhythms of vasoactive intestinal peptide and T lymphocyte subpopulations.

Recent investigations documented an immunosuppressive action of VIP. Previous studies demonstrated that T lymphocytes exhibit a circadian rhythm (CR). This investigation was, thus, performed with the aim of detecting the relationships intercurrent between the 24-h patterns of VIP and T lymphocyte subsets. The hypothesis was formulated that circulating VIP may play a role in controlling the CR of T cells. The research was carried out on 10 clinically healthy subjects, tested six times during the 24-h span by assaying circulating levels of VIP and total T (OKT3), T helper (OKT4), and T suppressor/cytotoxic (OKT8) lymphocytes. Time data series were analyzed by Cosinor method. All investigated variables were seen to be characterized by a statistically significant CR. While the acrophase of VIP CR was found to be located at 18.20, the crest of OKT3, OKT4, OKT8 CR was seen to occur at 03.04, 02.16 and 02.56, respectively. The phase shift was found to be significant, suggesting that VIP and T lymphocytes physiologically fluctuate with a phase angle during their nyctohemeral cyclicity. The finding can be regarded as an indirect evidence of a negative VIPergic chronoregulation of CR of T lymphocytes.