Influence of serum donor and recipient mouse genotype on the passive transfer of protective immunity with serum against Nematospiroides dubius

Immunological relationships during primary infection with Heligmosomoides polygyrus (Nematospiroides dubius): parasite specific IgG1 antibody responses and primary response phenotype

IgG1 antibody responses to Heligmosomoides polygyrus were measured in eight mouse strains supporting acute (< 8 weeks, SJL, SWR), intermediate (10-20 weeks, NIH, BALB/c) or chronic (> 25 weeks, C57BL/0, CBA, C3H, AKR) primary infections. Mice supporting acute or intermediate infections produced more intense antibody responses and total serum IgG1 concentrations were higher than in mice tolerating chronic infections. Positive correlations across mouse strains between the intensity of the antibody response and the percentage loss of worms in weeks 6 and 10 were established. No correlation was found between the response within mouse strains and loss of worms by individual mice. Heavy infections gave marginally higher antibody titres than low intensity infections, but few significant differences were detected and it was concluded that infection intensity did not markedly influence the magnitude of the antibody response. Male and female mice responded similarly despite the earlier loss of worms from females. No association was found between the primary response phenotype and recognition of particular antigens in Western blot analysis, nor did intensity of infection or host gender affect recognition. The possibility that immunomodulatory properties of adult worms may have had a differential influence on ability of strains of contrasting response phenotype to mount IgG1 responses was discussed.

Nematospiroides dubius: passive transfer of protective immunity to mice with monoclonal antibodies

Nine hybridoma cell lines secreting monoclonal antibodies specific for Nematospiroides dubius were produced by fusion of the mouse myeloma cell line NS-1 to either spleen cells or mesenteric lymph node cells from mice repeatedly infected with N. dubius. Seven of the antibodies were identified as IgM and two as IgG1. Each monoclonal antibody bound to polypeptide epitopes on both infective larvae (L3) and adult worms. However, five antibodies bound preferentially to L3 and three to adult worms. All nine antibodies reacted with high molecular weight protein antigens. Passive protective immunity in Balb/c mice was demonstrated with monoclonal antibodies Nd2 and Nd3 in ascites fluid which stunted both male and female worms and reduced parasite fecundity.

Heligmosomoides polygyrus: retarded development and stunting of larvae by antibodies specific for excretory/secretory antigens

The migration of young adult-stage Heligmosomoides polygyrus from beneath the muscularis mucosa to the lumen of the intestine was monitored to compare the rate of development and maturation of larvae in normal and previously infected mice. The development of surviving larvae was significantly retarded in mice that had experienced one or more previous infections and the adult worms arising from a challenge infection were stunted and appeared anaemic. Identical effects were observed with worms recovered from mice that had been injected with immune mouse serum at the time of challenge, and the magnitude of these effects was related to the amount of serum given. Larval maturation was also retarded in mice immunized with larval excretory/secretory (ES) antigens, even though the antibody response was poor due to the very small (submicrogram) amounts of antigen available for injection. In contrast, larvae developed at a normal rate in mice that had been hyperimmunized with killed exsheathed larvae. These mice had serum antibody titres against both "internal" and cuticular antigens similar to those of highly immune (4x-infected) mice, but they had no detectable antibody against ES antigens. The results indicate that the growth and development in vivo of H. polygyrus larvae are retarded by antibodies specific for larval ES antigens. Stunting is permanent, with female worms being affected more severely than males and egg output per worm correspondingly reduced.

Genetic control of immunity to Nematospiroides dubius: a 9-day anthelmintic abbreviated immunizing regime which separates weak and strong responder strains of mice

Experiments were designed to re-examine the variables which influence the ability of single primary infections to elicit acquired immunity to Nematospiroides dubius, in particular the importance of the presence or absence of adult worms, as these are known to exert immunomodulatory effects. Briefly, anthelmintic abbreviated infections were considerably more effective at eliciting acquired immunity than longer infections in which adult worms were allowed to reside in the intestine. A 9-day anthelmintic abbreviated infection was extremely effective at stimulation of acquired immunity in NIH mice and very few immunising infection larvae were required. Immunity to subsequent reinfection developed rapidly after the primary infection worms had been eliminated; by day 21 post-infection, the mice were almost totally immune. Abbreviated infections were used to examine the capacity of a number of mouse strains to develop immunity to reinfection. Strains of mice were chosen to allow the effects of MHC linked and non-MHC linked (background) genes to be identified. CBA and C3H strains (both H-2k) were found to be weak responders to N. dubius. B10G (H-2q) mice responded better than C57Bl/10 (H-2b), although these strains have identical background genes. DBA/2 mice were stronger responders compared to BALB/c mice, both strains sharing a common MHC haplotype (H-2d). (NIH X B10G) F1 mice (H-2q) were better responders than either of the parental strains. Several mouse strains all sharing the H-2q haplotype were particularly effective at developing immunity to N. dubius, as were also SJL mice which were the sole representatives of the H-2s haplotype, in the present study. The results established that the response phenotype is influenced by both background and MHC genes and demonstrated gene complementation in the capacity of mice to acquire immunity to N. dubius.

Host specificity in mice selected for innate immunity to Nematospiroides dubius: infections with Nippostrongylus brasiliensis, Mesocestoides corti and Salmonella typhimurium

The selection of mice for innate immunity to Nematospiroides dubius was not specific. Mice bred as refractory (R) to N. dubius infection were more refractory to primary infections with Nippostrongylus brasiliensis than other mice bred as liable (L) to infection with N. dubius. R and L, as well as randomly-bred (Rd) and inbred C3H mice were all immune to challenge infection with N. brasiliensis. Previous infections with N. brasiliensis failed to influence the course of N. dubius infections or the status of the selected mice as R, Rd and L to infection with N. dubius. R and L mice were equally susceptible to Mesocestoides corti infection but more resistant than Rd mice. R and L mice died sooner after infection with Salmonella typhimurium than Rd, although R survived longer than L mice.