Ae. Wild et al., IGG TRANSPORT ACROSS THE GUT OF THE SUCKLING OPOSSUM (MONODELPHIS-DOMESTICA), Developmental and comparative immunology, 18(1), 1994, pp. 75-88
We investigated IgG transport across the gut of suckling opossums to s
ee whether it is likely to be Fc gamma R-mediated. Enterocytes isolate
d from the proximal and distal regions of the small intestine of suckl
ings aged 12-52 days, and reacted with indicator SRBC at pK 6.0 or 7.2
, bound opossum IgG in rosette assays. Considerable overall variation
was observed in the numbers of enterocytes forming rosettes. No bindin
g was seen with rabbit IgG at these ages, or with opossum and rabbit I
gG when enterocytes were obtained from opossums aged 55-73 days. Oposs
um anti-SRBC antibody (IgG) fed to sucklings at 52 days and earlier (b
ut not later) could subsequently be detected in the serum. However, ra
bbit anti-SRBC antibody (IgG) could not be detected in the blood serum
when fed to sucklings of any age. Fluorescent tracing of FITC-labelle
d opossum and rabbit IgG fed to suckling opossums, and of endogenous o
possum IgG, pointed to transport of the homologous IgG occurring acros
s gut enterocytes of the proximal region. These results suggest that I
gG is recognised and transcytosed by specific Fc gamma Rs present on o
possum enterocytes prior to weaning.