Abstract
The impact on primary hemagglutinin titres in response to a challenge with a suspension of sheep red blood cells of treating male and female mice with naloxone or chlordiazepoxide was assessed. Naloxone increased total antibody titres in females but reduced it in males. This mu antagonist increased mercaptoethanol-resistant hemagglutinin titres in both males and females, with males showing the greater increase. Chlordiazepoxide reduced both total and mercaptoethanol-resistant antibody titre in both males and females, males showed a more marked suppression. Interestingly, naloxone is anxiogenic and chlordiazepoxide anxiolytic. The data suggest that treatment with psychoactive drugs is likely to influence disease resistance in organisms, data reminiscent of repeated claims that psychological factors influence immunoresponsiveness.