Attempts were made to induce antibody response of hapten primed cells by stimulation with anti immunoglobulin (Ig) antibody and cellfree supernatant (CFS) which contained nonspecific enhancing factor. Mesenteric lymph node cells were obtained from rabbits which were primed with dinitrophenylated ragweed antigen (DNP Rag), and the primed cells were incubated in vitro with either antirabbit γ chain or anti Fab antibody for 24 hr. After washing, the cells were cultured in CFS which was obtained from the culture of DNP Ascaris (DNP Asc) primed lymph node cells with free carrier (Asc). The results showed that hapten primed cells were triggered for IgG anti DNP antibody response by the 2 reagents, i.e., anti Ig antibody and CFS, both of which did not share any antigenic specificity with the priming antigen (DNP Rag). Neither anti Ig alone nor CFS alone induced anti hapten antibody response. Anti Ig and CFS triggered not only hapten primed B cells but also the other IgG bearing (B) cells from IgG synthesis. Lymph node cells of unprimed animals were activated for IgG synthesis by the stimulation with anti Ig followed by culture in CFS. Evidence was obtained that anti Ig antibody has to be divalent from the activation of B cells. Stimulation of DNP primed cells with the Fγ(ab')2 fragment of the antibody and CFS induced antihapten antibody response, whereas the Fab' fragment of the anti Ig plus CFS failed to do so. The results suggested that bridging of cell surface Ig receptors by multivalent ligand is the initial step of B cell activation. Another evidence for the activation of hapten primed B cells by anti Ig was obtained by supplemental immunization of DNP Asc primed animals with the Fc fragment of goat IgG. Stimulation of mesenteric lymph node cells from these animals with goat anti rabbit Ig alone (no CFS) resulted in the formation of anti DNP IgG antibody. The results indicated that lymphocytes primed for goat IgG collaborated with DNP primed IgG B cells when the lymph node cells were stimulated with goat anti Ig.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Immunology|
|Issue number||2 I|
|State||Published - Dec 1 1975|
ASJC Scopus subject areas
- Immunology and Allergy