Autovaccination of dairy cows to treat post partum metritis caused by Actinomyces pyogenes

Autovaccines are therapeutic vaccines manufactured from a disease causing m icro-organism for individual treatment of patients, animals. or sometimes h erds to treat chronic or recurrent infections. Despite the common use of au tovaccines in veterinary medicine, their mechanism of action, i.e. the immu nologic effector mechanism activated after administration, has never been i nvestigated. Here we present data concerning the use of autovaccines to tre at metritis infection in a group of dairy cows. Following autovaccination w e observed a significant decrease in CD4 + cells paralleled by an increase in T-cells expressing the gamma delta -T-cell receptor (gamma delta -TCR) i n the peripheral blood of the treated animals. Lymphocyte proliferation ass ays showed an initial increase in antigen-specific responsiveness followed by a decrease in this responsiveness during autovaccination treatment. We t herefore conclude that administration of an autovaccine leads to the activa tion of immunologic effector mechanisms which contribute to recovery of the diseased animals. (C) 2001 Elsevier Science Ltd. All rights reserved.