Philip A. Brunell

DETECTION OF ACUTE SERUM ANTIBODIES TO A/NEW JERSEY|[sol]|76 INFLUENZA VIRUS AFTER REMOVAL OF IgG WITH COWAN I STAPHYLOCOCCUS AUREUS

Cowan I strain of Staphylococcus aureus contains a cell wall substance, protein A, which can absorb most of the IgG from human serum; IgM, IgA, and IgD remain practically unaffected. In the present study, acute sera from children who received killed A/New Jersey/76 influenza virus vaccine were absorbed with S. aureus (Cowan I). An aliquot of the serum was also absorbed with S. aureus (Wood), a strain which does not contain protein A. A third aliquot was left unabsorbed. Hemagglutination-inhibiting (HAI) antibodies to A/New Jersey/76 antigen were determined on the three serum aliquots in tandem. The unabsorbed sera and sera which were absorbed with S. aureus (Wood) had comparable HAI antibody titers. The sera of 11 of 14 children had an eight-fold or less decline in HAI antibody titer after absorption with S. aureus (Cowan I); the sera of two other children decreased sixteen-fold. Only one childs serum had no detectable HAI antibodies after the absorption procedure with S. aureus (Cowan I). In contrast, the latter absorption completely removed HAI antibodies from the sera of a control group who had long-standing antibodies to A/New Jersey/76 (or an antigenically similar virus). The acute sera of the vaccinees which still contained HAI antibodies after S. aureus (Cowan I) absorption suggests the presence of specific IgM and/or IgA antibodies. This relatively simple absorption procedure performed on a single serum may be useful for the detection of an acute influenzal infection.