Specific and Cross-Reactive Activation of Rabbit Peripheral Blood Lymphocytes by Streptococcal Vaccines

Abstract

The ability of primed rabbit blood lymphocytes to respond in vitro to the homologous streptococcal group antigen depends on its presence in culture in the form of vaccine or cell walls thereof. These lymphocytes can also be stimulated in vitro by streptococcal vaccines with chemically related group antigens. The basis for this cross-stimulation apparently resides in shared rhamnose moieties. Activation of these lymphocytes was not achieved by vaccines from unrelated bacteria. There is also the suggestion that rabbits of different genetic origin differentiate between cross-stimulating antigens, probably at the level of antigenic determinants. The data support the view that recognition and response pattern of the immune system rely heavily on a network of antigens.

T Cell Activation of Primed Rabbit Blood Lymphocytes by Antigen

“…Briefly, PBL were prepared from arterial blood obtained from 6 rabbits (K20-232, K33-380, K.34^113, K45-426, K68-442, K40-512) that had been hyperimmunized 6 -1 2 months before the experiments reported here (3). Stimulation of PBL at optimal cell densities (2 X 10'' cells/ml) with the homologous A486 variant streptococcal vaccine was generally performed in microcultures (7,14,17), and 4C-or 3H-thymidine uptake was determined for 48 individual cultures simultaneously by a previously described method of harvesting microcultures (16). Demonstration of specific antibody to the Av-CHO produced in vitro was possible by the spot test and PFC assay performed with SRBC coated by the O-stearoyl-group Av-CHO ester (2,7,14,20).…”

“…antigen-dependent (20). Since neither pneumococcal nor Proteus vulgaris vaccines can be used as substitutes for stimulation and large numbers of PFC are generated in the presence of homologous vaccine or cell walls (consisting essentially of peptidoglycan and group-polysaccharide), stimulation is also antigen-specific (2,1,17). In addition, vaccines of streptococcal strains sharing a chemically related grouppolysaccharide antigen as cell wall moiety with the homologous vaccine also 1 In partial fulfilment of MD thesis, University of Freiburg, FRO.…”

“…This stimulation induces an early wave of proliferation (17,18) followed by the appearance of polysaccharide-specific PFC (2,7,20). Stimulation requires the presence of vaccine in culture, i.e.…”

“…Since neither pneumococcal nor Proteus vulgaris vaccines can be used as substitutes for stimulation and large numbers of PFC are generated in the presence of homologous vaccine or cell walls (consisting essentially of peptidoglycan and group-polysaccharide), stimulation is also antigen-specific (2,1,17). In addition, vaccines of streptococcal strains sharing a chemically related grouppolysaccharide antigen as cell wall moiety with the homologous vaccine also stimulate in a cross-reactive fashion; therefore, tire response is also cross-specific (17). It was, furthermore, estimated that a large proportion of cells (3-33% of all cells cultured in the presence of vaccine) participate in the response in a specific or cross-reactive manner (17,18).…”

“…In addition, vaccines of streptococcal strains sharing a chemically related grouppolysaccharide antigen as cell wall moiety with the homologous vaccine also stimulate in a cross-reactive fashion; therefore, tire response is also cross-specific (17). It was, furthermore, estimated that a large proportion of cells (3-33% of all cells cultured in the presence of vaccine) participate in the response in a specific or cross-reactive manner (17,18). Clonal expansion of B precursor cells yielded up to 5% cells secreting polysaccharide-specific antibody in day 30 40 cultures (7).…”