Augmented uptake of neuraminidase-treated sheep red blood cells: participation of opsonic factors.

Neuraminidase from Vibrio cholerae (VCN) was used to treat sheep red blood cells (SRBC) which were then incubated in vitro with murine peritoneal macrophages. The uptake of VCN-treated SRBC by macrophages was greater than the uptake of SRBC not treated with VCN. SRBC opsonized with normal mouse serum (NMS) were taken up to a greater extent than untreated SRBC. SRBC treated with VCN and opsonized with NMS were phagocytosed to a greater extent than untreated SRBC, VCN-treated SRBC, or opsonized SRBC. Evidence demonstrated that factors in serum from normal C3H/HeJ mice augmented the uptake of VCN-treated SRBC in greater amounts than of normal SRBC. These findings were discussed in relation to the increased immunogenicity of neuraminidase-treated cells.