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Updated: Feb 4, 2026

Sigma's Non-specific Protease Activity Assay - Casein as a Substrate
Published on: September 17, 2008
Immunoreactive properties of α-casein and κ-casein: Ex vivo and in vivo studies
Ewa Fuc1, Dagmara Złotkowska1, Emilia Stachurska1
1Department of Immunology and Food Microbiology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Tuwima 10, Olsztyn, Poland.
Abstract:
The aim of this study was to evaluate the ex vivo and in vivo studies immune potential of α- and κ-casein. Ex vivo, naïve mouse splenocytes were stimulated with α- or κ-casein. After 120 h of culture, the proliferation index (PI), determined by 3-(4,5 dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and carboxyfluorescein diacetate N-succinimidyl ester (CFSE) staining, did not vary for either antigen, suggesting similar ex vivo immunogenic potential of both casein fractions. In vivo, BALB/ccmdb mice were sensitized with α- or κ-casein and then gavaged with primary antigen. Mice immunized with α-casein had higher levels of IgG (216.33) and IgA (210.22) in serum at the end of the experiment compared with mice immunized with κ-casein (215 and 29.3 for IgG and IgA, respectively). The use of α-casein for mouse immunization and ex vivo lymphocyte stimulation resulted in higher concentrations of secreted cytokines (IL-4, IL-10) compared with κ-casein stimulation. This is consistent with increasing regulatory T cell (Treg) lymphocyte populations, independent of the antigen used for stimulation. In summary, the immunogenic potential of α- and κ-casein was similar. Humoral and cellular immune responses confirmed their strong, independent potential to induce B and T cells. We propose that the lymphocyte proliferation index be used as an initial screening for protein immunogenicity.
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