Immune response of a marsupial (Monodelphis domestica) to sheep red blood cells.

A study of the humoral immune response of a marsupial, Monodelphis domestica, was performed using sheep red blood cells as the immunogen and a hemolytic titration as the assay. The primary response to a single intramuscular injection was similar to that observed in other mammalian species, except that the titers remained high for as long as 37 weeks after the initial injection. The secondary response was weaker than the primary response and diminished as early as 15 weeks after the initial injection (and only 11 weeks after the single booster injection). The hyperimmune response was similar to the secondary response, except that the titers remained consistent for up to 10 weeks and then fell to very low levels at 35 weeks. The data support the view that the primary humoral response of this marsupial is similar to that of eutherian mammals. However, the secondary and hyperimmune responses appear to be very weak, if present at all.