Pneumococcal cell wall phosphorylcholine elicits polyclonal antibody secretion in mice

Abstract

Immunization of mice with phosphorylcholine (PC)-bearing Staphylococcus pneumoniae Type 2, strain 36a (R36a) results in both a PC-specific and a polyclonal increase in splenic plaque-forming cells. The polyclonal increase was observed in all strains tested, including those bearing an X-linked immune defect resulting in an undetectable anti-PC immune response. The magnitude of the polyclonal response is directly related to the amount of bacterial surface PC as detected by enzyme-linked immunosorbent assay. Congenitally athymic (nude) mice mount an anti-PC plaque-forming cell response after R36a immunization but fail to produce a significant polyclonal response. From our results it appears that PC on the cell wall of a bacterium acts both as a polyclonal activator and a specific antigen, stimulating each by different mechanisms.

Phosphorylcholine on isologous red blood cells induces polyclonal but not anti‐phosphorylcholine plaque‐forming cells in mice

“…NO evidence of anti-MRBC or anti-PC-MRBC antibody production could be detected. cytes [9] and human peripheral blood B cells (Levitt, D., unpublished results). This receptor is not an Ig molecule although it displays an epitope present on HOPCS anti-PC myeloma proteins, binds PC coupled to protein and may associate with PC on R36a bacteria.…”

“…However, soluble PC (PC-bovine serum albumin) failed to stimulate either type of Ig secretion after primary immunization [2]. We analyzed whether PC on isologous RBC induced either polyclonal or specific antibody secretion.…”

“…Spleen cells secreting total Ig, anti-PC, anti-TNP, anti-SRBC, anti-MRBC or anti-PC-MRBC were quantitated by either direct or protein A hemolytic plaque assays in agarose [2]. Correlation between anti-PC and protein A PFC were tested using the anti-PC-secreting hybridoma HPCM2 (IgM,x) as described previously 131.…”

“…Our previous studies demonstrated that PC and R36a-binding non-immunoglobulin (Ig) molecules are expressed on the surface of approximately 3-6% of murine B cells [9]. It was proposed that these receptors may help mediate polyclonal B cell activation by PC.…”