Immunogenicity of casein phosphopeptides derived from tryptic hydrolysis of beta-casein.
The immunogenicity of phosphopeptides derived from tryptic hydrolysis of beta-casein (CN) was investigated in a rat model system. The titers of specific immunoglobulin (Ig)G and IgE antibodies made in response to intraperitoneal sensitization to beta-CN, casein phosphopeptides, and skim milk proteins were examined using indirect and amplified indirect ELISA, respectively. Serum IgG antibodies from rats injected with beta-CN were significantly more reactive to beta-CN, casein phosphopeptides, and skim milk proteins coated on microtiter plate wells than were the IgG antibodies generated in rats that had been subjected to other treatments. A significant difference in titers because of the time of sampling (14 or 21 d postinjection) was noted for IgE but not for IgG. Rats that were injected with casein phosphopeptides did not produce IgG antibodies that crossreacted with either skim milk proteins or beta-CN. Specific antibody levels for the IgE class rarely exceeded those of unimmunized controls. The findings suggest that immunogenicity of the phosphopeptides was reduced compared with that of native beta-CN and skim milk proteins.
Heddleson
R A
RA
Southeast Dairy Foods Research Center, Department of Food Science, North Carolina State University, Raleigh 27695-7624, USA.
Park
O
O
Allen
J C
JC
D000818:Animals; D000917:Antibody Formation; D002364:Caseins / Q000276:immunology* / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006868:Hydrolysis; D007073:Immunoglobulin E / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D008894:Milk Proteins / Q000276:immunology; D010446:Peptide Fragments / Q000276:immunology* / Q000378:metabolism; D010537:Peritoneum / Q000276:immunology; D010750:Phosphoproteins / Q000276:immunology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014357:Trypsin / Q000378:metabolism*
D002364:Caseins; D007074:Immunoglobulin G; D008894:Milk Proteins; D010446:Peptide Fragments; D010750:Phosphoproteins; D007073:Immunoglobulin E; D014357:Trypsin