CO2 ANESTHESIA FACILITATES A SERUM ANTIBODY-RESPONSE TO ORALLY-ADMINISTERED ANTIGENS

Under most experimental circumstances, mice fed a protein antigen prod uce a smaller serum antibody response than the response elicited in mi ce that are parenterally immunized with that same antigen. In our expe riments, mice fed keyhole Limpet hemocyanin or herpes simplex virus ty pe 1 had low, if any, serum IgG antibody responses regardless of wheth er antigen consumption was voluntary (in drinking fluids) or involunta ry (force-fed by pipette). However, when force-feeding occurred during CO2 anesthesia, mice produced significantly higher serum antibody res ponses, which were comparable to those elicited in mice injected intra peritoneally with the same antigen. Although its mechanism of action i s unclear, this potentiating effect does not appear to be mediated by possible CO2 mediated entry of the antigens into the respiratory tract , since mice fed antigen immediately before CO2 anesthesia also had a substantial antibody response.