Antibody OKT3 Research Articles

Lymphocytes infiltrating human ovarian tumors. I. Role of Leu-19 (NKH1)-positive recombinant IL-2-activated cultures of lymphocytes infiltrating human ovarian tumors.

Tumor-infiltrating lymphocytes (TIL) were obtained from human ovarian tumors, expanded in the presence of IL-2 in culture and studied for cytotoxicity against fresh autologous and allogeneic ovarian carcinoma (CA) targets. TIL from ovarian tumors grew well in long term cultures, achieving from 8- to 682-fold expansion. TIL cultured with IL-2 were cytotoxic against both autologous and allogeneic fresh ovarian CA targets, and no specificity for autologous tumor could be demonstrated in any of the cultures. In all fresh TIL preparations, CD3+ lymphocytes were the major cell type and contained a high proportion (up to 51%) of activated (IL-2R+) cells as determined by two-color flow cytometry. Sorting of bulk TIL cultures followed by cytotoxicity assays identified the Leu-19+ cells, both CD3+ and CD3-, as effectors of cytotoxicity against autologous and allogeneic tumor cell targets. Cold target inhibition assays showed that allogeneic targets (both ovarian CA and a sarcoma) competed effectively with autologous ovarian CA targets for Leu-19+ effectors in TIL cultures. mAb to Leu-19 or Leu-2a did not block lysis of autologous targets by sorted effectors. OKT3 antibody augmented lysis of autologous targets by CD3+Leu-19- effectors only. These results show that non-MHC-restricted Leu-19+ effectors in cultures of TIL with 1000 U/ml of rIL-2 mediate lysis of autologous and allogeneic tumor cells. The CD3+Leu-19- cells, the main population in these cultures, do not mediate tumor lysis. To determine the phenotype of antitumor effectors in IL-2 cultures of TIL, cell sorting followed by functional assays are necessary.

Transferrin receptor expression by non-Hodgkin's lymphomas. Correlation with morphologic grade and survival.

The monoclonal antibody OKT9 was applied to cryostat sections of 267 non-Hodgkin's lymphomas and related neoplasms. It was found that the transferrin receptor is expressed by a wide variety of B- and T-lineage non-Hodgkin's lymphomas. The OKT9 staining also was loosely correlated with the three morphologic grades of non-Hodgkin's lymphomas identified by the International Working Formulation. In general, higher grade lymphomas more often and more intensely expressed the T9 antigen. However, transferrin receptor expression by certain histologic subtypes of lymphoma did not correlate with their morphologic grade: low-grade follicular lymphomas expressed the T9 antigen more frequently than diffuse low-grade lymphomas; diffuse small cleaved cell lymphomas were stained by OKT9 less often than other histologic subtypes of intermediate-grade lymphomas; and diffuse immunoblastic lymphomas expressed transferrin receptors less often than the other high-grade histologic subtypes of non-Hodgkin's lymphoma. Intermediate lymphocytic lymphomas, not recognized in the International Working Formulation, were infrequently and weakly stained by OKT9 in a manner similar to diffuse low-grade lymphomas. We obtained clinical follow-up data on 43 individuals with chronic lymphocytic leukemia/small lymphocytic lymphoma and 64 individuals with diffuse large cell and immunoblastic lymphoma. Transferrin receptor expression in these two groups did not correlate significantly with survival.

T cell-mediated production of tumour necrosis factor-alpha by monocytes.

The aim of this study was to examine the tumour necrosis factor (TNF)-alpha production by peripheral blood mononuclear cells activated by mitogens. Considerable amounts of TNF-alpha, ranging from 1.0 to 5.0 ng/ml, were present in the supernatants of cultures of human peripheral blood mononuclear cells (PBMC), stimulated with either the anti-CD3 monoclonal antibody OKT3 or the lectin phytohaemagglutinin (PHA). The amount of TNF-alpha secreted in the supernatant was closely correlated to the degree of T cell proliferation in such cultures, as measured by [3H]TdR incorporation. In the absence of proliferating T cells the mitogens did not induce secretion of TNF-alpha by monocytes. Supernatants of proliferating T cells were shown to induce TNF-alpha production by monocytes. The macrophage-activating factor gamma interferon (IFN-gamma) was also shown to induce, in the absence of endotoxin, TNF-alpha secretion by monocytes in a dose-dependent manner. The induction of TNF-alpha production by supernatants of proliferating T cells could largely be abrogated by passaging the supernatants on an anti-IFN-gamma column before adding them to the monocytes. It is therefore concluded from this study that the production of TNF-alpha by monocytes can be induced by proliferating T cells and that this induction can largely be attributed to the T cell lymphokine IFN-gamma.

Nosocomial Aseptic Meningitis Associated With Administration of OKT3

An outbreak of nosocomial aseptic meningitis involving four renal allograft recipients on the transplant service occurred in July 1986, shortly after the release of the murine monoclonal antibody OKT3 for therapy for acute allograft rejection. No bacteria, fungi, or viruses were isolated from cultures of the cerebrospinal fluid of the four patients. All four had acute allograft rejection treated with OKT3 and developed signs and/or symptoms of meningitis within 72 hours of receiving the drug. To identify potential risk factors, the four patients with aseptic meningitis were compared with 12 patients on the renal transplant service in July 1986 who did not have signs or symptoms of meningitis. The development of aseptic meningitis was strongly associated with administration of OKT3. Because of this association, prospective surveillance of meningitis in patients receiving OKT3 was instituted. From November 1986 to May 1987, three (14%) of 21 patients treated with OKT3 developed aseptic meningitis. The clinical course of aseptic meningitis associated with OKT3 appears to be benign and self-limited. Nonetheless, this observation warrants continued surveillance of OKT3 therapy.

Nosocomial aseptic meningitis associated with administration of OKT3

An outbreak of nosocomial aseptic meningitis involving four renal allograft recipients on the transplant service occurred in July 1986, shortly after the release of the murine monoclonal antibody OKT3 for therapy for acute allograft rejection. No bacteria, fungi, or viruses were isolated from cultures of the cerebrospinal fluid of the four patients. All four had acute allograft rejection treated with OKT3 and developed signs and/or symptoms of meningitis within 72 hours of receiving the drug. To identify potential risk factors, the four patients with aseptic meningitis were compared with 12 patients on the renal transplant service in July 1986 who did not have signs or symptoms of meningitis. The development of aseptic meningitis was strongly associated with administration of OKT3. Because of this association, prospective surveillance of meningitis in patients receiving OKT3 was instituted. From November 1986 to May 1987, three (14%) of 21 patients treated with OKT3 developed aseptic meningitis. The clinical course of aseptic meningitis associated with OKT3 appears to be benign and self-limited. Nonetheless, this observation warrants continued surveillance of OKT3 therapy.

Resting metabolic rate of the critically III patient: Measured v predicted : Weissman C, Kemper M, Askanazi J, et al. Anesthesiology 64:673, 1986

Local immunocompetence was evaluated immunohistochemically in patients with bladder tumors before and after local injections of an immunomodulator. The subpopulations of tissue infiltrating lymphocytes (TIL) were examined by staining six serial sections with Leu4, Leu7, LeulO, LeuM3, OKT4, and OKT8 antibodies. T cells predominated over B cells in 19 of 25 bladder tumors. T cell infiltration was prominent around tumor cells, and it was marked in non-invasive tumors. B cells were rare in the stroma. In patients with low-stage tumors, OKT8 cells were more prominent than OKT4 cells. NK cells accumulated within cancer nests but their infiltration was scanty in invasive bladder tumors. Before surgery, immunomodulators (OK-432, IL-2) were injected intratumorally. Their administration resulted in marked increase of T and NK cells, irrespective of the stage of disease; there was a slight increase in B cells. These findings suggest that local immunosurveillance plays a role against bladder tumors. Further studies are required to elucidate host immune responses in the microenvironment of the cancer site, as well as the systemic immune reaction.

Induction of human in vitro IgE synthesis via stimulation by anti-CD3 antibody.

Mitogens such as pokeweed mitogen, Staphylococcus aureus Cowan I, concanavalin A and phytohemagglutinin and monoclonal anti-CD antibodies were examined for their capacity to induce IgE synthesis by peripheral blood leukocytes obtained from both atopic and nonatopic individuals. While lectins failed to induce IgE synthesis, monoclonal anti-CD3 antibodies were very potent stimuli for the induction of human in vitro IgE synthesis, possibly due to the activation of T cells. Activation via CD4 or CD8 molecules by OKT4 or OKT8 antibodies did not lead to a T cell-dependent modulation of IgE synthesis. PWM acted in synergy with the enhancing effect of anti-CD3 antibodies for IgE synthesis. In vitro IgG production was less affected. These results indicate that activation of T cell via CD3 molecules may be important in the regulation of IgE immune responses in man. Furthermore, the successful induction of IgE synthesis by anti-CD3 antibody in unfractionated peripheral blood leukocytes culture provides a simple model for investigation of human IgE regulatory mechanism in vitro.

Functional Significance of Anti-T-Lymphocyte Antibodies in Sarcoidosis

Pulmonary sarcoidosis is a chronic disorder characterized by the activation of helper/inducer T-cells in the lung without a concomitant increase in suppressor/cytotoxic T-cells. It is known that patients with sarcoidosis have circulating anti-T-cell antibodies, primarily of the IgM class. To evaluate a functional role for these antibodies in enhancing lung helper T-cell processes in pulmonary sarcoidosis, we evaluated serum and lavage fluid of patients with active sarcoidosis for the presence of anti-T-cell antibodies, the T-cell subset specificity of these antibodies, and the possible stimulatory or inhibitory effects of these antibodies on T-cells relevant to the exaggerated helper T-cell processes in sarcoidosis. Indirect immunofluorescence studies demonstrated that sarcoid patients had anti-T-cell antibodies of the IgM type reacting with autologous as well as with nonautologous normal T-cells. IgM recovered in sarcoid lavage fluid also reacted with T-cells, thus demonstrating the autoantibodies at the site of disease. Two-color immunofluorescence and flow cytometry showed that these sarcoid autoantibodies bound to mostly Leu2+ suppressor/cytotoxic T-cells, but also to a small proportion of Leu3+ helper/inducer T-cells. Incubating lymphocytes with sarcoid serum or IgM purified from sarcoid serum did not stimulate T-cell proliferation. Furthermore, when Leu2+ T-cells were stimulated with irradiated allogenic B-cells, increasing concentrations of sarcoid serum had no inhibitory effects on the activation and proliferative response of the Leu2+ T-cells. Likewise, the purified IgM anti-T-cell antibodies had no inhibitory effects on the mitogenic response of Leu2+ T-cells to the anti-T-cell antigen receptor-associated T3 complex antibody OKT3.(ABSTRACT TRUNCATED AT 250 WORDS)

A major 50-kDa human B-cell growth factor-II induces both Tac antigen expression and proliferation by several types of lymphocytes

Many cytokines have been documented to have a multiplicity of biological effects by acting on a variety of cells. In order to determine whether human BCGF-II acts on any cells in addition to normal B cells, the effect of human BCGF-II on murine thymocytes, human peripheral blood T cells, a human natural killer-like cell line, YT, and Epstein-Barr virus (EBV)-transformed B-cell lines was further examined. BCGF-II augmented incorporation of [ 3H]thymidine by murine thymocytes in combination with suboptimal doses (0.5 μg/ml) of concanavalin A (Con A) but not at lower doses (0.1 μg/ml) of Con A, a concentration usually used for interleukin 1 (IL-1) assays. BCGF-II could not induce proliferation or Tac antigen (Ag) expression on normal peripheral blood T cells stimulated with OKT3 antibody. Both proliferation and Tac Ag expression on YT cells were also augmented by BCGF-II. BCGF-II induced both high- and low-affinity IL-2 receptor (IL-2R) on YT cells as determined by 125I-IL-2-binding assay. Two of seven EBV-transformed B-cell lines tested (ORSON and AUM cells) in response to BCGF-II exhibited augmentation of proliferation and cell surface Tac Ag expression. BCGF-II in the presence of low doses (0.1 μg/ml) of phorbol myristate acetate (PMA) also induced Tac Ag mRNA (3.5 and 1.5 kb) in these B-cell lines. The IL-2R induced on these B-cell lines, however, consisted mostly of low-affinity receptors. Both Tac Ag and its mRNA in these B-cell lines were not induced by Forskolin but by PMA, suggesting that this induction may involve protein kinase C. The present study shows that human BCGF-II can stimulate YT cells, murine thymocytes, and some EBV-transformed B-cell lines but not peripheral blood T cells. Consequently, BCGF-II can induce the growth and differentiation of a number of cell types in addition to normal B cells.

A Comparison of OKT3 Monoclonal Antibody and Corticosteroids in the Treatment of Acute Renal Allograft Rejection

The monoclonal antibody OKT3 (Ortho Pharmaceutical, Raritan, NJ) was utilized in two separate protocols for treatment of acute renal allograft rejection in patients receiving cyclosporine, azathioprine, and prednisone for maintenance immunosuppression. In Group I, 54 patients received steroids for primary treatment of acute rejection with OKT3 used for resistant rejections and second rejection episodes. In Group II, 34 patients received OKT3 as primary treatment of acute rejection while steroids were used for rescue and second rejection episodes. OKT3 successfully reversed 82% of initial acute rejection episodes in Group II as compared with a 63% reversal with steroids in Group I. Rescue treatment was required in only 15% of Group II patients compared with 33% of Group I patients. Overall patient survival was 96% and 94%, respectively, for steroid primary and OKT3 primary treatments. Allograft survival at 3 months was identical, 74% in both groups. Based on allograft survival data, OKT3 is equally effective either as primary treatment for allograft rejection, or for rescue therapy if initial corticosteroid treatment fails.

Experience with OKT3 in Vascularized Pancreas Transplantation

With refinements in technical aspects of whole organ pancreas transplantation, allograft rejection is currently the major cause of graft failure. The monoclonal antibody OKT3 has emerged as a highly effective antirejection therapy in renal and hepatic allograft recipients, but its efficacy in pancreas transplantation remains to be determined. During a 12-month period, 28 vascularized whole organ pancreas transplants were performed with pancreatico-cystostomy. Sixteen episodes of allograft rejection were treated with monoclonal antibody OKT3. Indications for OKT3 use included steroid- or antilymphocyte globulin (ALG)-resistant allograft rejection in isolated pancreas (n = 8) or simultaneous kidney-pancreas (n = 8) transplants. A total of 34 rejection episodes occurred in the 16 patients (mean, 2.1; range, one to five). The diagnosis of rejection was based on clinical criteria, a reduction in urinary amylase clearance, radionuclide scanning, hyperglycemia, or associated renal allograft dysfunction in combined engraftments. Postoperative immunosuppression consisted of cyclosporine, prednisone, azathioprine, and prophylactic ALG. OKT3 was administered for a full 14-day course concomitant with low-dose steroids, azathioprine, and cyclosporine. The mean age of the patient population was 32.1 years (range 24 to 39) with a mean duration of insulin-dependent diabetes mellitus (IDDM) of 20.9 years. Monoclonal antibody therapy was instituted in two clinical settings: early rejection (within 3 months of transplant, n = 10); and late rejection (after 3 months, n = 6). OKT3 successfully reversed allograft rejection in ten (62.5%) cases, including six early (60%) and four late (66.7%) episodes. In isolated pancreas transplants, OKT3 therapy reversed pancreas allograft rejection in only two patients (25%).(ABSTRACT TRUNCATED AT 250 WORDS)

REEXPOSURE TO OKT3 IN RENAL ALLOGRAFT RECIPIENTS

Between 40% and 80% of patients treated with the monoclonal antibody OKT3 develop blocking antibody against its idiotypic region. Thus a major concern with the use of OKT3 as part of a baseline immunosuppressive regimen is that formation of blocking antibodies might preclude its subsequent use. Between 7/86 and 2/87, 32 patients received prophylactic OKT3 in addition to low-dose prednisone, azathioprine, and cyclosporine. Prophylactic OKT3 did not prevent rejection, as 21 of 32 patients studied developed rejection. Retreatment of 13 patients with OKT3 successfully reversed 12 rejections and lowered the number of T3-positive cells in spite of a low level of blocking antibody in two patients in this group. Of the patients analyzed, 38% developed blocking antibody on initial exposure to OKT3, but OKT3 reuse was denied only 4 patients due to the presence of these antibodies. Three of these had rejections reversed with steroids alone; the other patient lost the allograft. A high frequency of infectious complications occurred in the retreatment group, with viral infections predominating. Only one patient in the retreated group developed antibodies after the second use. Appearance of blocking antibodies after use of OKT3 as part of a base-line prophylactic immunosuppressive regimen did not significantly compromise access to OKT3 for treatment of subsequent rejection episodes, but multiple exposures to OKT3 did increase the frequency of infectious complications.

Isolation of an HTLV-1-like retrovirus from patients with tropical spastic paraparesis.

Tropical spastic paraparesis (TSP) is a slowly progressive myelopathy associated with increased serum and cerebrospinal fluid antibodies to the human T-lymphotropic retrovirus type I (HTLV-I) (ref. 1), and has been observed in many regions of the world. A similar condition known as HTLV-I-associated myelopathy occurs in the Kagoshima prefecture of Japan. Recent but controversial reports suggest involvement of virus related to HTLV-I in multiple sclerosis. Magnetic resonance imaging and electrophysiological studies indicate that TSP lesions are like multiple sclerosis in that they are disseminated throughout the nervous system. Complete virus from patients with TSP has proved difficult to isolate using techniques successful in adult T-cell leukaemia cases associated with HTLV-I. Here we report the isolation of an HTLV-I-like virus from T-cell lines derived from the peripheral blood and cerebrospinal fluid of TSP patients. The monoclonal antibody OKT3 was used to generate non-transformed T-cell lines that express HTLV-I antigens. Infectious virus was demonstrated by co-cultivation and complete, replicating virions were visualized ultrastructurally.

Accumulation of Langerhans' Cells on the Epithelial Surface of the Lower Respiratory Tract in Normal Subjects in Association with Cigarette Smoking

Langerhans' cells are a defined subpopulation of the mononuclear phagocyte system known to accumulate in the lung in histiocytosis X, an interstitial lung disorder strongly linked to cigarette smoking. To evaluate the hypothesis that cigarette smoking itself may be associated with the accumulation of Langerhans' cells in the lung, normal nonsmokers (n = 5) and normal smokers (n = 10) were evaluated by bronchoalveolar lavage for the presence of Langerhans' cells as identified by the OKT6 monoclonal antibody and by transmission electron microscopy. While the OKT6 antibody identified 0.1 +/- 0.1% of the cells recovered from nonsmokers, it labeled 1.1 +/- 0.3% of those recovered from smokers (p less than 0.01). Furthermore, while electron microscopy demonstrated no Langerhans' cells among the lavage cells from nonsmokers, 0.4 +/- 0.1% of the cells recovered from normal smokers contained characteristic intracytoplasmic Birbeck granules, positively identifying them as Langerhans' cells. We conclude that cigarette smoking is associated with an expansion in the population of Langerhans' cells on the epithelial surface of the lower respiratory tract. While the mechanisms underlying this accumulation are unknown, it is possible that the properties of these cells contribute to the derangements of the pulmonary parenchyma found in cigarette smoking and establish a biologic link to the already observed epidemiologic association between histiocytosis X and cigarette smoking.

Interferon-alpha induction of lymphocytes containing parallel tubular structures.

The induction by IFN-alpha in peripheral blood lymphocytes of parallel tubular structures (PTS) and/or electron-dense granules occurring in a minority of peripheral blood lymphocytes was examined. IFN reportedly augments natural killer (NK) cell activity of large granular lymphocytes (LGL); these cells contain PTS and/or electron-dense granules. Normal peripheral blood mononuclear cells were incubated with IFN-alpha and surface antigen expression was measured by means of indirect immunofluorescence and, at the ultrastructural level, using gold labelled monoclonal antibodies. Surface antigen reactivity with the monoclonal antibodies OKT 3, 4, 8 and Anti-Leu-7 (HNK-1) showed no difference between the IFN-alpha incubation and non-IFN-alpha groups. However, electron microscope investigation revealed significant absolute increases in the percentage of OKT 8+ and Anti-Leu-7+ cells which were PTS-positive after IFN-alpha treatment compared with the control groups. The cytotoxicity assay using the K562 cell line showed enhanced lytic activity. Our results suggest that cells coexpressing the OKT 8 and Leu-7 antigens may be responsible for a minor proportion of the increase in PTS but that IFN-alpha mainly induces PTS and/or associated structures in cells which express the OKT 8+ antigen. These PTS+/OKT 8+ cells may contribute to enhanced cell cytotoxicity.

Increase in cytoplasmic free calcium concentration initiated by T3 antigen stimulation is imparied in adult T-cell leukemia cells

We studied the change in cytoplasmic free calcium ion concentration ([Ca 2+] i) in the peripheral blood leukemic cells from adult T-cell leukemia (ATL) patients stimulated by anti-T3(CD3) or anti-T11(CD2) antibodies in order to see whether there is an abnormal response in the early activation processes following T3 or T11 antigen stimulation. Peripheral blood mononuclear cells (PBMC) from four T-cell chronic lymphocytic leukemia (T-CLL) patients showed a rapid and clear increase in [Ca 2+] i (from 165 ± 26 nM to more than 299 nM) when stimulated by OKT3 antibody and anti-mouse IgG antibody. This response was comparable to that of PBMC from 10 normal individuals (from 151 ± 20 nM to 252 ± 34 nM). In contrast, PBMC from 10 ATL patients showed only a slight increase in [Ca 2+] i (from 137 ± 21 nM to 176 ± 32 nM) following T3 stimulation. The experiments with higher concentrations of OKT3 antibody suggested that this attenuated increase in [Ca 2+] i in ATL cells was not exclusively due to impaired expression of T3 antigen. The [Ca 2+] i increase in ATL cells induced by the stimulation with two anti-T11 antibodies recognizing different epitopes of the T11 antigen, however, was comparable to that of normal PBMC. The abnormal response of [Ca 2+] i to the T-cell receptor /T3 antigen stimulation in ATL may be related to dysfunction or leukemogenesis of HTLV-I-infected cells.

Lymphocyte subsets in relation to immunosuppression in Mycoplasma pneumoniae pneumonia

Lymphocyte proliferative response to mitogens and skin testing for delayed hypersensitivity to tuberculin were diminished during acute phase of Mycoplasma pneumoniae pneumonia. We analyzed peripheral blood lymphocytes from patients in the acute phase of illness, convalescent phase of illness and after recovery using monoclonal antibodies Bl, OKT3, OKT11, OKT4, OKT8, OKIA1, Leu7 and Leull. In the acute phase of illness a peripheral lymphocytopenia was found. The percentage of OKT3 positive lymphocytes and the absolute number of Bl, OKT11, OKT3, OKT4 and OKT8 positive lymphocytes were decreased in the acute phase of illness. In the convalescent phase of illness, tuberculin test and the absolute number of lymphocytes, OKT11, OKT3 and OKT4 positive lymphocytes returned to normal. The absolute number of OKT8 positive lymphocytes were still decreased. As a result, helper-suppressor ratio (OKT4/OKT8) was increased during convalescence. After recovery, lymphocyte proliferative response to mitogens and lymphocyte subsets became normal. These results demonstrate that the transient immunosuppression in the acute phase of Mycoplasma pneumoniae pneumonia is probably caused by peripheral lymphocytopenia, T lymphocytopenia and reduction of helper/inducer lymphocytes.

The Immunoarchitecture of the Normal Human Lacrimal Gland: Relevancy for Understanding Pathologic Conditions

To delineate the immunoarchitecture of the normal human lacrimal gland, monoclonal antibodies that detect B- and T-lymphocyte, macrophage, and dendritic cell lineage, subset, and differentiation-associated antigens were used in combination with highly sensitive tissue-section immunoperoxidase techniques. Plasma cells, identified with monoclonal antibody OKT10, represented the predominant mononuclear cell population, accounting for 53.9% of all mononuclear cells present. A qualitative study of plasma cell cytoplasmic immunoglobulin heavy-chain expression in deparaffinized, formalin-fixed tissue sections showed that the vast majority of these plasma cells contained IgA. Rare plasma cells contained IgG, IgM, or IgD. T-cells, identified with monoclonal antibody OKT3, represented the second most common cell type in the normal human lacrimal gland, accounting for 40.3% of all mononuclear cells present. T cells were located predominantly in lymphocyytc foci and singly in the interstitium. T8 antigen-positive (suppressor/cytotoxic) T cells predominated over T4 antigen-positive (helper) T cells, averaging 25.2 and 14.7%,respectively. The overall mean T4/T8 ratio was 0.56. T8 antigen-positive T cells were the most numerous cell population outside aggregates and follicles, being distributed almost equally between the acini and the ducts (49%) and the interstitium (51 %). Only 16% of T4 antigen-positive cells preferred glands or ducts to the interstitium. B cells, identified with monoclonal antibody BL9, represented only 5.7% of all mononuclear cells present. B cells were exclusively found in the centers of primary and secondary follicles. The majority of the surface immunoglobulin-positive B cells expressed IgM, fewer expressed IgD, and still fewer expressed IgG or IgA. Rare LeuM1+ OKM1+ macrophages were present in the center of B-cell follicles, where rare OKT6+ dendritic cells and activated T cells (IL-2+) were also discovered. These results support the concept that the lacrimal gland belongs to the mucosa-associated lymphoid system.

Induction of expression of cell-surface homologous restriction factor upon anti-CD3 stimulation of human peripheral lymphocytes.

Homologous restriction factor (HRF) is a 65-kDa membrane protein that inhibits transmembrane channel formation by the membrane-attack complex of complement and by the complement component C9-related cytolytic lymphocyte protein. Stimulation of resting peripheral human lymphocytes with the anti-CD3 monoclonal antibody OKT3 has been shown to induce cytotoxicity in the CD8+ subpopulation. As demonstrated here, OKT3 stimulation also induces expression of cell-surface HRF by CD4+ and CD8+ T lymphocytes. The small proportion of Leu 19+ natural killer lymphocytes present in peripheral blood mononuclear cells was found to express HRF prior to stimulation. Whereas unstimulated peripheral blood mononuclear cells were susceptible to lysis by the membrane-attack complex or by the C9-related protein, OKT3-stimulated peripheral blood mononuclear cells were relatively resistant to both the membrane-attack complex and C9-related protein. This acquired resistance was abrogated by blocking surface HRF with F(ab')2 anti-HRF, suggesting that resistance was due to lymphocyte-membrane HRF. By using solid-phase anti-HRF, a 65-kDa protein was isolated from the activated peripheral blood mononuclear cells and shown to be capable of conferring upon sheep erythrocytes the characteristic activity of human HRF.

Conjunctival lymphocyte subsets in trachoma

Monoclonal antibodies were used to assess the lymphocyte populations in conjunctival biopsy specimens obtained from patients with trachoma (active or inactive) undergoing tarsotomy for the correction of trachoma-induced entropion and in three control patients. Peroxidase-labelled monoclonal antibodies OKT4 (identifies T-helper/inducer lymphocytes), OKT8 (identifies T-suppressor/cytotoxic lymphocytes), OKIal (identifies B-lymphocytes) and antisera specific for IgG, IgA and IgM were used to identify lymphocyte subpopulations and immunoglobulins in the conjunctival biopsy specimens. When grouped by disease activity, conjunctival tissue specimens revealed predominant T-helper/inducer lymphocytes in the substantia propria of patients with active trachoma while inactive trachoma patients had predominant T-suppressor/cytotoxic lymphocytes in the conjunctival biopsy specimens. B-lymphocytes were seen in moderate numbers in all conjunctival biopsy specimens from patients with active trachoma and all specimens from active cases stained for IgG, IgM, and IgA. Immunoglobulin staining was strongest with IgG and IgM.