Lack of Opsonization Potential of 11S Human Secretory A

Pure human colostral 11S secretory γA anti-A isoagglutinin was compared with serum γG and γM as to opsonic activity against A red cells in a system containing either human monocytes or neutrophils. Some preparations of secretory γA had functional activity only in the presence of fresh serum. This activity could be absorbed out by a cross-linked anti-μ chain antiserum. No evidence was found to support the view that 11S secretory γA has an opsonic function in this system.