In Vitro Responses of CBA/N Mice: Spleen Cells of Mice with an X-Linked Defect that Precludes Immune Responses to Several Thymus-Independent Antigens Can Respond to TNP-Lipopolysaccharide

Abstract

Spleen cells from CBA/N mice with an X-linked B cell defect were examined for their ability to form antibody in vitro after stimulation with the T-independent antigen TNP-LPS. In contradistinction to their failure to respond to some conventional T-independent antigens such as type III pneumococcal polysaccharide or DNP-AECM-Ficoll, spleen cells from (CBA/N × DBA/2)F₁ male mice were able to make a specific anti-TNP PFC response after culture with TNP-LPS. Their response differed from that of phenotypically normal (CBA/N × DBA/2)F₁ female litermate spleen cells in that more TNP-LPS was required to elicit the peak anti-TNP response and the anti-TNP antibody secreted by F₁ male cells was of lower avidity than that of F₁ female cells. The polyclonal antibody response to unsubstituted LPS did not differ substantially between normal and defective B cells. Thymus-derived cells were not required for the TNP-LPS response by either F₁ male or female cells. We conclude that CBA/N B cells can respond to certain T-independent antigens that are able either to induce a very strong activating signal upon ligand-surface receptor interaction and/or to stimulate immature B cells (with a characteristic high surface immunoglobulin profile) which fail to respond to antigens like DNP-AECM-Ficoll.