Following immunization with bacteria (i.e. Salmonella johannesburg), rabbit spleen lymphocytes developed a specific blast response when the lymphocytes were stimulated with polysaccharide, the haptenic moiety of lipopolysaccharide. A clear cut dissociation was noted in the blast response induced by polysaccharide compared with those induced by lipopolysaccharide and lipid A. There was no correlation between the magnitude of the cellular responses and that of the antibody response. Moreover, there was less specificity at the cellular level than at the level of antibody secreted by cells. A decrease of 3H-thymidine incorporation was often observed after immunization, at the level of peripheral blood lymphocytes. An inhibitory effect of these cells was shown on the blast response of spleen lymphocytes with polysaccharide. A high blast response to Salmonella polysaccharide which could be observed in some non-immunized rabbits might be related to a natural sensitization of animals with the same or related unknown antigens which could not be recognized by anti-S. johannesburg antibodies.
Inhibition of circulating antibody production by steroids has been repeatedly shown in steroid-sensitive animals such as mice or rabbits. It is well known that after a single injection of 5 mg of cortisone acetate, mouse spleen cells loose their ability to be transformed by B cell mitogens such as lipopolysaccharides or Nocardia water soluble mitogen. Therefore it was of interest to study in the rabbit the influence of cortisone on the reactivity of spleen cells to a B cell mitogen (blast transformation and polyclonal strimulation) and their ability to be cytotoxic in the antibody-dependent cell-mediated cytotoxicity assay. Our data demonstrate that the cells which mediate such a cytotoxicity are cortisone-resistant whereas the B lymphocytes--which can be transformed and polyclonally activated by these mitogens--are sensitive to cortisone treatment.
The humoral response to influenza A/PR8 virus was examined in the CBA/N and C3J.xid strains of mice, both of which bear an X-linked genetic defect (xid), and in strains lacking this defect. Hemagglutination-inhibiting antibody titers and measurement of virus-specific antibodies by solid-phase radioimmunoassay indicated that the xid defect does not impair the production of an adequate anti-influenza antibody response. However, investigation of the isotypes of PR8 virus-specific antibodies disclosed a relative decrease in the levels of IgG3 and IgG1 in the xid-bearing strains. This was observed after both intraperitoneal immunization and aerosol infection. The isotype differences were not reflected in the susceptibility of these strains to influenza virus infection.
A panel of monoclonal antibodies specific for a corresponding panel of sequentially selected variants of influenza A/PR/8/34 virus has been established. Although the monoclonal antibodies are paratypically distinct, idiotypic relatedness has been observed. Two cross-reactive idiotypes have been defined that are associated with the 7183 and S107 VH gene families, respectively. Three of the four monoclonal antibodies utilize the VK21 group of light chains, and three VH genes belong to the VH7183 family and one to the VH S107 family. Antibodies encoded by genes deriving from the VH7183 family share a cross-reactive idiotype, a marker of the VH region as well as distinct individual idiotopes. These antibodies are produced by different clones using related VH and VK genes.
The idiotype defined by the levan-specific BALB/c myeloma protein ABPC48 (A48) has previously been encountered only in antibodies the variable regions of which derive from the VHX24 and V kappa 10 gene families. We have demonstrated expression of the idiotope recognized by the monoclonal anti-A48 idiotype antibody IDA10 on five monoclonal antibodies from different mouse strains, with different specificities including foreign and self antigens and deriving their variable regions from families other than VHX24 and V kappa 10. We analyzed variable region protein structure (deduced from nucleotide sequences) and hydrophilicity profiles of idiotype+ and idiotype- antibodies. We identified four surface-exposed areas (one in the heavy chain and three in the light chain) that may contribute to expression of the idiotope defined by antibody IDA10.
It has been previously observed that lipopolysaccharides can be detoxified by alkylation and yet retain their adjuvant activity. Our present findings confirm these results and show, moreover, that these derivatives did not lose their capacity to protect mice against lethal irradiation and lost only partially their ability to interrupt pregnancy or to induce blast transformation of murine B-lymphocytes. However, in contrast with lipopolysaccharides, these alkylated preparations did not enhance the nonspecific resistance of mice to a bacterial infection. The various bilogical functions of endotoxins can therefore be separated and are not uniformly related to their toxicity.
Behaviour of normal and hydrolase-treated guinea-pig lymph node lymphocytes versus heterologous ALS was studied by means of biophysical and immunological techniques i.e. electrophoretic mobility, leucoagglutination, cytotoxicity and visualization of antigen–antibody reaction in electron microscopy.
Our results clearly revealed that heterologous ALS antibodies reacted with mannose and sialic acid containing glycoproteins located on the lymphocyte surface. Sialic acid and other main constituents of the lymphocyte cell coat, i.e. the sulphated mucopolysaccharides have an important role in the electronegative charges of the cell and in binding of the ALS antibodies.
β-Glycosidase as well as α-maltase treatment of the lymph node lymphocyte increased from 45% to 100% the reactivity to ALS as revealed by the peroxidase reaction in electron microscopy.
These results suggest that all lymph node lymphocytes can react with ALS antibodies, but that the reactive sites of 45% of these cells are masked by glucidic sub-units.
We investigated the growth and differentiation of leukaemic B cells from patients with B‐cell chronic lymphocytic leukaemia (CLL) in response to proliferation and differentiation factors present in conditioned medium and to anti‐immunoglobulin antibodies. Highly purified E‐rosette negative (E) B cells from 5 out of 15 patients with CLL exhibited moderate proliferative responses to Ml or 10 or 15 μ/ml of F(ab′) 2 fragments of rabbit anti‐human μ‐chain specific antibody. Conditioned medium (CM), derived by stimulating human peripheral blood mononuclear leucocytes with PHA. induced significant proliferative responses of purified E cells in 13 out of 14 patients examined. The extent of these proliferative responses varied substantially, and was in the range of 2.6‐ to 91‐fold. Stimulation of purified L cells trom patients with CLL with both anti‐μ and CM resulted in significant proliferative in all l5 patients examined. These responses were significantly higher than thosc induced by CM alone (P<0.02). Synergism between CM and anti‐μ in inducing proliferative responses was observed in 11 out of 15 patients. Largely loukaemic B cell populations expressing on the cell surface more than one immunoglolobulin heavy chain isotype, exhibited significantly higher (P<0.009) proliferaiive response to CM and anti‐μ than those expressing IgM only. Highly purified E‐ peripheral blood or tonsil lymphocytes from all normal donors examined responded by proliferation to anti‐μ alone or to CM alone. Synergism in inducing prolifcrative responses was aiso observed when the cells were stimulated with both CM and anti‐μ. In addition to inducing proliferative responses, culture with CM of purified E‐rosctte negative, largely leukaemic, B cells from patients with CLL for 6 days at 37°C resulted in differentiation into immunoglobulin synthesizing and secreting cells. Synthesis and secretion of IgM were observed in 7 out of 10 patients examined. A switch to IgG production was observed in three patients. Morphological examination of E cells from patients wiih CLL after treatment wiih CM dcmonstrated thai these cells were differentiated into plasma‐like cells. These results suggest that leukaemic B cells from palicnls with CLL can be induced to proliferate and differentiate in response to growth and differentiation factors derived by mononuclear Icucocytes. in a manner similar to that of normal B cells.
