To measure serum IgA and IgG levels in experimental animals, blood specimens from
experimental mice were collected from infraorbital veins using capillary tubes
on day 7 or 21 after the first oral administration of each strain of LAB. To
obtain serum samples, each blood sample was incubated on ice for 1 h and
centrifuged at 8,000×g for 10 min. Each serum sample was then diluted
1:100 with PBS for measuring IgA and IgG levels (Choi et al., 2017 (
link)). Sandwich ELISA kits were used to measure total
serum IgA (Cat # 88-50450-22, Thermo Fisher Scientific) and IgG (Cat #
88-50400-22, Thermo Fisher Scientific) levels according to the
manufacturer’s instructions.
To measure BALT IgA, bronchoalveolar lavage was performed with 2 mL PBS after
exposing the tracheae of sacrificed mice. Bronchoalveolar lavage fluids were
then centrifuged at 800×g for 5 min at 4°C (Choi et al., 2018 (
link)). Levels of IgA in bronchoalveolar lavage
fluids were quantitated using sandwich ELISA kits (Cat # 88-50450-22, Thermo
Fisher Scientific).
To measure GALT IgA, LPCs from Peyer’s patches were isolated from the
small intestine of each sacrificed mouse according to previously established
method (Kikuchi et al., 2014 (
link)). Isolated
LPCs (2.5×10
5 cells/well) were then mixed with each
heat-killed LAB (5×10
6 CFU/mL) and seeded into 96-well plates
in 200 μL of RPMI 1640 medium supplemented with 10% (v/v) FBS and 1%
penicillin/streptomycin. After 2 days of incubation, culture supernatants of
each sample were harvested and sandwich ELISAs were performed to detect IgA
levels using ELISA kit (Cat # 88-50450-22, Thermo Fisher Scientific).
Choi C.Y., Lee C.H., Yang J., Kang S.J., Park I.B., Park S.W., Lee N.Y., Hwang H.B., Yun H.S, & Chun T. (2023). Efficacies of Potential Probiotic Candidates Isolated from Traditional Fermented Korean Foods in Stimulating Immunoglobulin A Secretion. Food Science of Animal Resources, 43(2), 346-358.