Some Immunological Relationships of α-Lactalbumin and β-Lactoglobulin in Milks of Various Species

Separate rabbit antisera prepared against cow a-laetalbmnin and fl-lactoglobulin were found in Oudin diffusion tests and on Ouehterlony plates to react with the milk of some, but not all, of a variety of species.A high degree of cross reaction was found with the milks of other ruminants (goat, sheep, and water buffalo), but not with the milks of the nonruminants tested (camel, horse, rat, mouse, guinea pig, pig, dog, and rabbit).The antiserum to cow B-lactoglobulin reacted with sheep milk about three times as strongly as with cow, goat, and buffalo milk, and the antiserum to cow a-laetalbumin reacted about twice as strongly with the goat and buffalo milk as with cow or sheep milk.Comparative analyses using crystalline fl-laetoglobulins isolated from cow, sheep, and goat milks indicated that the antiserum to cow B-laetoglobulin reacted more strongly with sheep and goat fi-lactoglobulin than with cow fi-lactoglobulin itself.When the analyses are corrected on this basis, it is possible to analyze sheep and goat (and probably buffalo) milk for their fl-laetoglobulin contents by using the antiserum to cow fl-laetoglobulin.These results appear to agree with the contents of fl-laetoglobulin indicated in these milks by other procedures.