Transfer of maternal immunoglobulins and antibodies to Mycoplasma gallisepticum and Mycoplasma synoviae to the allantoic and amniotic fluid of chicken embryos.

Maternal antibodies can protect avian embryos against vertically transmitted pathogens during embryogenesis and also young birds after hatching. In contrast to the well-known transfer of maternal immunoglobulin (Ig) G (also termed IgY) from the yolk to embryonic blood, information about the transfer of IgA, IgG and IgM from the egg albumen to the extra-embryonic fluids is very limited. In our study, IgA, IgG and IgM to Mycoplasma gallisepticum and Mycoplasma synoviae were detected in oviduct washings of naturally infected hens and in the corresponding egg albumen samples. In their progeny embryos, IgA, IgG and IgM antibodies to these Mycoplasma species were detected in the allantoic fluid (ALF) and amniotic fluid (AMF) on day 14 of embryonic development (ED). Examination of embryos from chickens immunized with antigens of M. synoviae revealed that the appearance of IgA and IgG and of antibodies to M. synoviae in ALF could vary even among embryos of the same dam. However, IgA, IgG and IgM were detected as early as day 7 of ED in ALF and AMF in certain embryos from hens infected with M. synoviae. In five groups of embryos examined on day 7, IgG to M.synoviae was found in 51% of ALF and 33% of AMF samples. M. synoviae was isolated from 2.3% of ALF samples. IgA to M. synoviae appeared in ALF and AMF on day 12 of ED, and could be found in the majority of AMF samples examined from day 14 onwards. IgM to M. synoviae appeared in AMF on day 13 and in ALF on day 14, but was detected in those fluids less frequently than IgA or IgG.