The effect of undernutrition on immunological responses to BCG and TAB vaccines in mice maintained on a natural diet.

A study was made on the effect of undernutrition on the immunological responses of mice to TAB and BCG vaccines. The mice were fed a diet comprising chapati and germinated grams; one group was fed ad libitum while another was given half the quantity consumed by the first group. The undernourished mice showed a poor immune response to BCG: only 23% showed a positive reaction to foot pad challenge with purified protein derivative, compared with 76% of the well-fed mice. The mean increase in thickness of the foot pad was also significantly smaller in the undernourished mice. Antibody titres against the H and O antigens of TAB were essentially similar in both groups of mice. The results suggest that undernutrition depresses cell-mediated immune responses but not humoral responses.