Characterization of Nippostrongylus brasiliensis infection in different strains of mice.

Five mouse strains, CBA/J, BALB/c, C3H/HeJ, A/J, and C57Bl/6J-bg-bg, all showed similar expulsion kinetics for Nippostrongylus brasiliensis (infective dose = 500 L3). Typically, parasite recovery was maximal on day 2 in the lungs and by day 4 in the small intestine. Few worms (less than 5% infective dose) were recovered on day 14 in all strains. These same mouse strains exhibited immune depression on day 5 of infection with mesenteric lymph node cells (MLN) showing reduced (10-30% normal) IgM, IgG, and IgA responses against heterologous antigen. The intestinal mast cell numbers and tissue histamine levels were examined in CBA/J mice. Mast cell numbers increased (normal = less than 1/villous crypt unit; VCU) from day 5 and peaked on day 12 (greater than 15/VCU). Intestinal histamine levels did not completely correlate with mast cell numbers with maximum concentrations (240 +/- 73 ng/g, 2-fold over normal) reached by day 8. Histamine concentrations in the intestine returned to normal levels by day 20.