SERUM AND MILK ANTIBODY LEVELS TO GIARDIA LAMBLIA

Abstract

There is little data relating to the prevalence and role of systemic and local antibody to Giardia lamblia (GL) antigens in mothers and children living in different environments. We obtained human milk and serum specimens from mothers and children living in Dacca, Bangladesh, Baltimore (MD) Houston (TX) and Mexico City. We compared the prevalence and levels of milk IgA and serum IgG antibodies to GL in the different populations by means of an ELISA assay utilizing purified antigens from cultured GL organisms. We found that 101/104 (97%) mothers living in Bangladesh, 22/26 (84%) mothers living in Maryland 9/17 (52%) mothers living in Texas and 23/37 (67%) mothers living in Mexico had detectable levels of milk IgA antibody to GL. The levels (geometric mean +/- SD) of antibody in the milk samples from mothers in Bangladesh (11.25 +/- .16μg/ml) and Mexico (17.69 +/- 1.22 μg/ml) were significantly greater than the levels detected in the women living in Maryland (1.78 +/- 1.11μg/ml) or Texas (1.70 +/- .097 μg/ml). In terms of total milk IgA, the IgA directed at GL in Bangladesh (1.54%) and Mexico (3.20%) were significantly greater than the corresponding percentages in Maryland (0.59%) and Texas (0.70%). Analysis of serial specimens obtained from lactating mothers over a period of 2 years revealed that most of the mothers had a constant level of antibody, although occasional increases in milk and serum antibody levels were noted. These studies indicate that serum and milk antibodies to GL are widely prevalent throughout the world but that the levels of milk antibody are significantly higher in areas of high exposure to GL.