A preparation of crude flagella contaminated with vesicle, believed to be derived from the flagellar sheaths, when injected without adjuvant at a dose of 1 micron subcutaneously into female mice at the time of mating permits them to transmit a high level of passive immunity to their nursing babies. This immunity can be neutralized by the intragastric administration of rabbit anti-mouse IgA. The work to be done during the next period of support is aimed at an analysis of the nature of the immunity conferred and why it is superior to that of other vaccines. This will be done through the use of anti-mouse IgG and IgM, which must be prepared, and by attempting to determine the affect of the immunoglobulins on vibrio motility. This is relevant since nonmotile mutants that are fully toxinogenic are avirulent. In addition to the infant mouse model, similar studies will be done with the infant rabbit and with isolated ileal loops of rabbits.