Spontaneous Plaque-forming Cells Research Articles

Immunoregulatory aberrations in patients with polyarticular juvenile rheumatoid arthritis

The presence of hypergammaglobulinemia and various circulating autoantibodies in children with polyarticular juvenile rheumatoid arthritis (JRA) implies an immunoregulatory disorder. We report here experiments planned to elucidate the underlying cellular aberrations in this disease. Twelve children with polyarticular JRA were studied. Percentages of Leu-1, Leu-2, and Leu 3 T cells were comparable to those of normal individuals. Immunofluorescent double staining studies demonstrated elevated numbers of activated (DR +) T cells of both Leu-2 and Leu-3 phenotype. B cells characterized both phenotypically (Leu-12) and functionally (as spontaneous plaque-forming cells, PFC) were elevated. In vitro PFC responses to pokeweed mitogen (PWM) and Epstein-Barr virus (EBV) were diminished. The levels of concanavalin A-induced suppressor cells of the PWM-stimulated PFC responses were comparable to control values. In contrast, the EBV-associated suppressor T cells were significantly impaired in both EBV-seropositive and EBV-seronegative patients. These studies indicate that peripheral blood B-cell activity is abnormal in polyarticular JRA. Defective T-cell responses in vitro suggest that this may be due to disruption of normal regulatory circuits between B and T cells and may contribute to the pathogenesis of this disease.

Polyclonal antibody secretion during acute graft-versus-host disease.

Spontaneous plaque-forming cells (S-PFC) were followed in 67 bone marrow transplantation (BMT) recipients and 41 controls. Patients with no acute graft-versus-host disease (GVHD) had decreased IgA and IgM S-PFC up to 7 weeks after BMT compared with controls. Patients with acute GVHD had increased IgG, IgA, and IgM PFC compared with controls and patients without GVHD during the first 4 weeks after BMT. The maximum number of S-PFC increased with increasing severity of acute GVHD. However, at diagnosis of GVHD there was no difference in S-PFC in patients who resolved their GVHD or in those who developed more severe GVHD. After 6 weeks, patients with acute GVHD had significantly decreased IgA and IgM S-PFC compared with normal. No major changes in S-PFC were induced during various infections. However, a patient who developed urticaria had a dramatic increase in S-PFC. Patients studied more than a year after BMT had reduced IgM S-PFC compared with controls. It is concluded that S-PFC are reduced after BMT, but markedly enhanced during acute GVHD.

Effect of drug therapy on circulating and synovial fluid Ig-secreting cells in rheumatoid arthritis.

A common immunological abnormality in rheumatoid arthritis (RA) is an increased spontaneous polyclonal B cell activation. In order to study the influence of drug therapy in RA on the functional activity of B cells we enumerated spontaneous plaque-forming cells (PFC) in peripheral blood lymphocytes (PBL) and synovial fluid lymphocytes (SFL) by a reverse haemolytic plaque assay. Spontaneous IgG-, IgM-, and IgA-PFC in PBL of 26 patients with classical erosive RA receiving either gold salts or D-penicillamine were similar to those observed in 20 healthy controls. In contrast, significantly higher numbers of IgG- and IgA-PFC, but not IgM-PFC, were found in PBL of nine patients with classical erosive RA receiving non-steroidal anti-inflammatory drugs (NSAID) alone. Furthermore, spontaneous PFC in SFL from 16 consecutive patients with RA receiving second-line drugs, as well as 17 patients with other forms of arthritis (non-RA) were generally low and significantly less than those observed in 20 RA patients on NSAID alone. Moreover, a wide individual variation in PFC, especially in relation to the IgG class, was recorded in the synovial lymphocytes. These studies imply that treatment with second-line drugs is associated with normalisation of B cell activity in RA patients, and that the effect can be detected at the cellular level both in blood and synovial fluid.

Polyclonal B-cell activation and increased lymphocyte helper-suppressor ratios in discoid lupus erythematosus.

We studied polyclonal B-cell activation in twenty-six patients with discoid lupus erythematosus (DLE). Spontaneous plaque-forming cells of the IgA class (IgA-SPFC) as determined by a reverse haemolytic plaque assay were significantly more common in patients with DLE than in fifty control subjects. The patients showed a positive correlation between IgA-SPFC and OKT4/8 ratios and also had a significantly higher mean OKT4/8 ratio. The two groups did not differ with regard to cells producing IgG or IgM or cells with OKT3, OKT4, OKT8 or OKMI markers. None of the three patients with DLE who had IgA-SPFC values which were above the mean (+2 s.d.) for the control subjects had positive tests for ANA or low serum C3 or C4, but two of the three also had increased IgG-SPFC values. The results indicate that polyclonal B-cell activation occurs in a small proportion of patients with DLE.

Evaluation of B-cell, T-helper-cell, and T-suppressor-cell function in patients with Graves' disease before and after treatment with anti-thyroid drugs

Spontaneous and pokeweed mitogen (PWM)-induced immunoglobulin-secreting B cells were evaluated in 20 newly diagnosed Graves' disease patients, and 11 of the patients were retested when euthyroid after treatment for 6–10 months with anti-thyroid drugs. Numbers of spontaneous plaque-forming cells (PFC) in patients tested before or after treatment were not significantly different from age- and sex-matched controls, but PWM-induced IgG-, IgA-, and IgM-PFC were significantly reduced in the pretreatment group to approximately one-half the mean control value. After treatment, numbers of PFC were midway between pretreatment and control values. Reduced B-cell activation was not due to circulating in vivo activated suppressor cells nor reduced T helper function. Concanavalin A-induced T suppressor function was normal in all but 2 20 pretreatment and 1 11 post-treatment patients.

Abnormalities of immunoregulatory T cell subsets in patients with insulin-dependent diabetes mellitus.

Patients with insulin-dependent diabetes mellitus (IDDM) have autoantibodies that react with cells in the islets of Langerhans. To determine whether these patients suffer from a more generalized immunoregulatory disorder, the ratio of phenotypic helper to suppressor cells was evaluated by specific monoclonal antibodies. Our experiments showed that the helper/suppressor cell ratio was significantly increased in patients with IDDM of less of 2 mo duration and then gradually returned to normal. Despite the alteration in the helper/suppressor cell ratio, there was no evidence for polyclonal activation as measured by the number of immunoglobulin-secreting plaque-forming cells in the peripheral blood. There was, however, a significant increase in the number of spontaneous plaque-forming cells in patients suffering from both IDDM and Hashimoto's thyroiditis (HT). Nonetheless, immunoglobulin production after stimulation with pokeweed mitogen was not different in diabetics with or without HT when compared to normal controls. These findings suggest that subtle changes in the immunoregulatory system occur during the early stages of IDDM.

Development of immune potential and migration pattern of cells from germfree (GF) and conventionally (CONV) reared rats.

Absence or low levels of natural antibodies, immunoglobulins and spontaneous plaque-forming cells described in GF animals of some species [piglets (1,2), sheep (3), rabbits (4,5)] indicate that significant levels of natural antibodies can arise as the consequence of inapparent immunization by environmental antigens. Also the rapid increase in the capacity to form antibodies after imunization during first weeks of life in conventional conditions contrasting with the relatively stable level of the response in GF piglets (1) point to the role of microflora antigens in the postnatal maturation of the immune system (1–3,5). On the other hand, there exist animal species, e.g. mice, in which even in GF environment the immunological capacity and presence of natural antibodies is comparable to that of CONV reared counterparts (6,7).KeywordsSalivary GlandMesenteric Lymph NodeNatural AntibodyEnvironmental AntigenPostnatal MaturationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Single Mouse Cells Producing Two Antibody Molecules and Giving Rise to Antigen-Driven Intraclonal Variation after Immunization with Two Unrelated Antigens

Abstract Hemolytic plaque-forming cells (PFC) simultaneously lysing two different hapten-red cell indicators (double PFC) appear regularly along with PFC lysing only one indicator, on the 4th to 5th day of secondary response in mice primed 2 to 4 months before with hapten-protein conjugates mixed in Freund's complete adjuvant. Addition of soluble-specific inhibitors, i.e., the same haptens conjugated to different protein-carriers, results in an inhibition of the corresponding specific lytic activity and the disappearance of the double PFC. Micromanipulation of these cells from the initial medium into a second medium, containing both indicator RBC and one specific inhibitor, inhibited the corresponding specific lysis in 80% of double cells without affecting the unrelated lytic activity. Subsequent micromanipulation into a third inhibitor-free medium resulted in a recovery of the double lysis in more than 50% of them. This evidence for the synthesis of two different antibody molecules by double PFC was further strengthened by individual cell culture experiments; most of these cells divided and engendered daughter PFC-secreting antibody of only one of the two specificities, thus showing first, the transient nature of double production, and second, that each lytic activity can be inherited separately. Individual cell cultures also showed occurrence of clonal variation in progeny of single PFC. Among PFC from mice immunized with two antigens to progeny variation occurred in 24 out of 46 (0.656) parental cells as against only 1 out of 40 (0.025) observed among individual PFC from animals immunized with one antigen. Moreover, this variation was antigen driven since absence for 48 hr of the one antigen resulted in discontinuance of generation of daughter PFC of the corresponding specificity. A similar degree of antigen-driven variation was observed when spontaneous PFC or PFC arising early after immunization (2nd or 3rd day) with one antigen were individually cultured for 48 hr with a different antigen; one part of parental PFC (0.545) yielded variant daughters of the specificity of the latter antigen, whereas the other part (0.455) yielded progeny of the same as the parental PFC specificity in a clonal manner. These results suggest that differentiation of B cells during the early phase after antigenic stimulation would involve a process of intracellular selection and/or rearrangement of V genes.

Studies of Congenitally Immunologic Mutant New Zealand Mice

Abstract Congenitally athymic (nude) mice on an NZB, NZW, and BALB/c background were produced by repetitive selective backcrossing. F'12 generation nude mice of these three strains were compared to their littermate nu/+ controls with respect to survival, histology, blood counts, splenic surface markers, response to mitogens, spontaneous plaque-forming cells, and appearance of naturally occurring thymocytotoxic antibodies (NTA). Under specific pathogen-free conditions, NZB nude mice survive less than 3 weeks, dying of a runting-like disease with infection by local normally noninvasive organisms. A contributing factor to this premature death is the relative absence of T cell progenitor populations in the NZB nude vs NZW nude or BALB/c nude groups. Furthermore, NZB nude mice have a significantly earlier appearance of NTA than nu/+ littermates and likewise appear to have heightened spontaneous polyclonal B cell responses against the haptens dansyl, nitroiodophenyl, trinitrophenyl, 2,4 dinitrophenyl, and sulfonate. It is suggested that NZB mice have several critical immunologic defects, including abnormalities of thymic epithelial cells, T cell differentiation pathways, and chronically polyclonal activated B cell populations. These defects interact to produce the clinical expression of autoimmunity.

Spontaneous plaque-forming cells against autologous erythrocytes develop in cultures of normal rabbit appendix cells

Cultured appendix and, to a lesser extent, mesenteric lymph node cells from normal, unimmunized rabbits spontaneously develop PFC against several erythrocyte species, including sheep erythrocytes (SRBC), trypsin-treated, autologous erythrocytes (TRRBC), and, most importantly, untreated, autologous erythocytes (RRBC). Cells from most other lymphoid tissues of the rabbit, including the spleen, fail to develop spontaneous, anti-autologous PFC in culture. This failure seems to be due to a lack of appropriate precursors among the cells comprising their populations, rather than to an inhibition by some suppressor cell population. The development of spontaneous PFC in vitro, and their virtual absence among appendix cells freshly removed from the rabbit implies an effective regulation on their expression in situ. This regulation may involve, in part, antigen itself. The development of the anti-autologous RRBC specificities may be a consequence of the intimate association of the gut-associated lymphoid tissue with the rich antigenic milieu in the intestinal lumen, part of which may present antigens cross-reactive with self antigens.