THE EFFECT OF CALORIC SUPPLEMENTATION ON SELECTED MILK PROTECTIVE FACTORS IN UNDERNOURISHED GUATEMALAN MOTHERS

The level and avidity indices of specific antibodies against tetanus t oxoid, Escherichia coli O6 and a pool of 10 common E. coli O antigens, as well as the concentration and daily output of lactoferrin and tota l secretory IgA (SIgA), were evaluated in the milk of moderately under nourished mothers who were in a random blind design divided into two g roups and given different caloric supplementations. Group A received a high caloric supplement (500 kcal/d), and group B received a low calo ric supplement (140 kcal/d). Determinations were done using ELISA in v arious modifications, except for lactoferrin, which was quantified by single radial immunodiffusion. The avidity indices were investigated a s an evaluation of the antibody quality. In all the parameters evaluat ed, the only difference found between the two groups at the end of the supplementation period was in the content of total SIgA, which was lo wer in group B, both in concentration and daily output. However, the S IgA remained within the normal range. Increases as well as decreases i n the levels of specific IgA antibodies occurred within both groups. A vidity was decreased in group B only against one of the antigens teste d. We conclude that moderate undernutrition does not impair the levels of milk antibodies, and supplementation does not enhance them but pre vents the decrease in the content of total milk SIgA. There is a sugge stion that the avidity of certain antibody specificities could be hamp ered.