To analyze the subclass restriction of Ag-specific IgA, sera and saliva from healthy blood donors and from IgA class or subclass deficient individuals were studied. The latter included donors with or without Cα1 or Cα2 gene deletions. Monoclonal human IgA1 and a genetically engineered IgA2 antibody, normal human serum and colostrum IgA were used as standards to estimate serum and saliva levels of Ag-specific antibodies. In normal individuals, there was a strong IgA1 preference of naturally acquired antibodies in serum against both polysaccharide Ag (PPS 6A, PPS 23, pneumococcal C-polysaccharide, and LPS from Escherichia coli) and protein Ag (Staphylococcus aureus α-toxin and HSV). Specific IgA2 in serum against the tested Ag were frequently not measurable. In contrast, most of the individuals with homozygous Cα1 gene deletions displayed substantial amounts of specific IgA2 against protein as well as polysaccharide Ag. The median levels of specific IgA in serum against protein Ag were approximately one-third as compared to normal individuals and one-fifth, or less, against polysaccharide Ag. Normal serum levels of IgA against the tested Ag, restricted to the IgA1 subclass, were noted in two individuals with IgA2 deficiency, one of whom carried a homozygous Cα2 gene deletion. Median values of specific IgA, against the tested Ag S. aureus α-toxin, HSV, and pneumococcal C-polysaccharide, from normal healthy donors were approximately four to eight times higher in serum as compared to saliva. Individuals with homozygous Cα1 gene deletions displayed increased levels of the various specific IgA2 antibodies in saliva. In conclusion, the individuals with homozygous Cα1 gene deletions displayed decreased median levels of specific IgA antibodies in serum despite normal levels of total IgA. Normal levels of both specific IgA and total IgA in saliva were found.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of Immunology|
|State||Published - Jul 1 1990|
All Science Journal Classification (ASJC) codes
- Immunology and Allergy