Regulation of IgG responses by helper and suppressor T cells activated by pneumococcal capsular polysaccharides

Humoral immune response to Klebsiella capsular polysaccharides in HLA-B27-positive patients with acute anterior uveitis and ankylosing spondylitis

Klebsiella is suggested to trigger ankylosing spondylitis (AS) and acute anterior uveitis (AAU) in HLA-B27-positive individuals. Previous investigations showed an increased antibody response to the Klebsiella capsular types K26, K36, and K50 in sera from HLA-B27-positive AS patients. In the present study the prevalence and titers of antibodies against Klebsiella capsular antigens were measured by means of an ELISA in 32 sera from HLA-B27-positive AAU patients either with (n = 10) or without AS (n = 22) and compared with sera from HLA-B27-negative AS-patients (n = 13). Sera from either HLA-B27-positive (n = 45) or negative (n = 40) healthy individuals served as control. Sera from HLA-B27-positive AAU with or without AS showed significantly higher antibody prevalence and IgG-titers against capsular antigens of the Klebsiella serotypes K26, K36, and K50 when compared with sera from HLA-B27-negative AS patients or with healthy controls. These results might be taken to indicate the predominance of these serotypes in the HLA-B27-associated AS and AAU.

Serum antibodies to Klebsiella capsular polysaccharides in ankylosing spondylitis

OBJECTIVE

To measure antibodies to Klebsiella capsular polysaccharides in the sera of HLA-B27 positive patients with ankylosing spondylitis (AS), compared with HLA-B27 positive and HLA-B27 negative healthy control subjects.

METHODS

Antibodies were detected by means of an enzyme-linked immunosorbent assay specific for each of the 77 known Klebsiella serotypes.

RESULTS

Significantly elevated frequencies and titers of antibodies to capsular polysaccharides K26, K36, and K50 were detected in sera from AS patients, compared with controls.

CONCLUSION

These results suggest the predominance of Klebsiella serotypes K26, K36, and K50 in patients with AS.

The amplifier role of T cells in the human in vitro B cell response to type 4 pneumococcal polysaccharide

The human B cell response to T cell independent type 2 antigens is regulated by thymus-derived lymphocytes. We analyzed the role of T cells in the in vitro antibody response to type 4 pneumococcal polysaccharide (PS4). We here show that the amplifying effect of T cells, which has previously been shown to be radioresistant and confined to T cell preparations enriched for CD4+ cells, is MHC non-restricted as demonstrated in cultures carried out in the presence of allogeneic T cells. Also, T cell clones derived from non-related donors are able to enhance the B cell response to PS4. All TCR alpha beta +, CD 4+ T cell clones, but none of the TCR alpha beta +, CD 8+ T cell clones tested, enhanced the B cell response to PS4. Furthermore, 3 out of 6 TCR gamma delta+ T cell clones were capable of enhancing the anti-PS4 B cell response. Experiments using recombinant lymphokines and glutaraldehyde-fixed T cells indicated that both lymphokines and T-B cell interactions are required for an optimal antibody response to PS4.

The human in vitro anti-type 4 pneumococcal polysaccharide antibody response is regulated by suppressor T cells

In order to study the regulation of the human B-cell response to T-cell independent type 2 (TI-2) antigens, we analysed the role of T cells in the in vitro antibody response to type 4 pneumococcal polysaccharide (PS4). We found that T cells can positively regulate the in vitro antibody response to PS4 when they are added into an in vitro B-cell culture system. In addition we demonstrated that T cells exert a negatively regulating activity. We found that T cells, when cultured for 24 h in the presence of high concentrations of PS4, can suppress the anti-PS4 antibody response. This down-regulation of the anti-PS4 B-cell response is shown to be antigen specific and MHC-restricted. Furthermore, PS4-specific T-cell mediated suppression appears to be radioresistant and confined to the T-cell preparations enriched for CD8+ cells. The results show that analogous to results obtained in mice, human T cells are able to exert a regulatory control of the antibody response to TI-2 antigens.