Mitogen Stimulation of Rabbit Spleen Cells before and after Complement-Mediated Cell Kill with an Antiserum Directed against the Thymus Antigen RTLA

Abstract

Rabbit thymus lymphocyte antigen (RTLA) has been previously characterized as an antigen of rabbit thymus-derived cells (Cell. Immunol. 7: 484–501, 1973). It has now been shown that the antigen may be regarded as a thymus marker in terms of cellular responsiveness to various mitogens. It was found that only RTLA-bearing spleen cells responded to phytohaemagglutinin and concanavalin A with increased thymidine uptake. Only those spleen cells, which remained viable after treatment with RTLA antibody and complement, responded by thymidine incorporation to antibody against A4 light chain marker. The sensitivity of the detection of mitogen effects was improved by removing cells, adhering to or ingesting magnetic core particles, coated with poly-L-lysine. Following such pretreatment, there was a reduction in thymidine uptake by unstimulated spleen cells. This reduction in background thymidine incorporation made it possible to determine target specificity with mitogens of low potency. Using this technique, it became possible to demonstrate that lipopolysaccharide is a mitogen for rabbit B cells, albeit marginally so, and much less effective for rabbit than for murine B cells.

Idiotypic Determinants on Rabbit B‐ and T‐Derived Lymphocytes

“…The majority of studies on rabbit T and B lymphocytes were carried out with cells from irradiated and reconstituted rabbits, or with lymphocytes in which one or the other sub-populations were killed with specific antisera (Fanger et al 1972, Fradelizi et al 1973, Shek et al 1974, Watanabe et al 1975. We have developed a technique for a quantitative separation of rabbit T derived lymphocytes which would not involve cell killing (Cavaillon et al 1977).…”

Functional Analysis of Murine and Human B Lymphocyte Subsets

“…Rabbit spleen cells respond to Nocardia extract (Bona et al 1974, Shek et al 1975, crude preparations of SIII (Shek et al 1975) and, weakly, to LPS (Shek et al 1974, Bona et al 1974. Spleen cell populations fractionated by velocity sedimentation and which lack mitogen responsive T cells respond to these ligands (Shek et al 1975) and responses to LPS are not reduced by removal of T cells using a cytotoxic anti-T cell serum (Shek et al 1974). The production of immunoglobulin by these stimulated B cells has not been reported.…”

Modulation of regulatory mechanisms operative in the cyclical production of antibody.

“…Since a strict comparison has not been made in the mouse between in vivo and in vitro effects of PHA on the PFC response to a particular antigen, it is possible that PHA acts via different mechanisms under in vivo and in vitro conditions. Furthermore, although PHA has been shown to be a mitogen for a subpopulation of T cells in both mice (36) and rabbits (25,37), and there appears to be a similarity in the function of different cell types in the mouse and rabbit (38), subtle differences have become apparent (39) which might result in PHA acting via different mechanisms in the mouse and rabbit. In addition, an in vivo effect of PHA in stimulating B cells directly cannot be ruled out since PHA also binds to B cells in the mouse (40) and is capable of stimulating B cells in vitro under conditions in which it is locally concentrated (41).…”