Increased CD4⁺ T cell‐dependent anti‐erythrocyte antibody levels following the onset of parasite egg production in Schistosoma mansoni infected mice

Abstract

Anaemia has been reported to be a symptom of schistosomiasis mansoni. In other chronic infectious diseases, anti-red blood cell (RBC) antibodies have been suggested or shown to play a role in anaemia by participating in either complement or macrophage-dependent RBC elimination. To examine whether such a situation could be contributing to the anaemia of schistosomiasis, we examined RBC taken from infected mice for surface-bound antibodies. Our data show that prior to the onset of egg production infected mice have plasma haemoglobin levels that are indistinguishable from age matched controls (AMC). However, consistent with previous reports, following the initiation of egg laying, infected mice have significantly lower haemoglobin levels than AMC. Surface-bound IgM, IgG1 and IgG3 on RBC from infected mice increased markedly after egg laying began. Levels of RBC-associated IgG2b were similar on RBC from infected and normal mice. Antibody production against RBC was Th cell-dependent since it did not occur in mice depleted of CD4+ cells. Antibodies eluted from RBC of infected mice bound to isolated membranes of RBC from AMC and to a soluble extract of schistosome eggs. Furthermore, antibodies in serum from mice carrying patent infections bound to the membranes of RBC from normal mice. Taken together, these data suggest that schistosome eggs induce an antibody response which may cross react with a RBC surface antigen.

Immunology of human schistosomiasis: off the beaten path

“…For example, the potent anti‐inflammatory agent dexamethasone reduces anaemia in experimentally infected mice (23). In addition, in schistosome‐infected mice and rabbits, anaemia is most pronounced during the acute phase of infection, but subsequently resolves as the infection enters the chronic phase and the intensity of the immune response modulates (24,25). In a murine model of hepatosplenic schistosomiasis, anaemia in some animals worsened as the infection became chronic (26).…”

“…Car washers in Kenya with high levels of S. mansoni infection report increased tolerance for certain food types following treatment with praziquantel (Dr Diana Karanja, personal communication). Other mechanisms suggested in schistosome‐related anaemia include development of antibodies against RBCs in schistosome‐infected mice (25), production of haemolytic factors by S. japonicum (28) and S. mansoni (29), haemolytic anaemia associated with splenomegaly (30), and iron‐deficiency anaemia brought about by malnutrition or blood loss in schistosomiasis patients (31).…”

Anti-HSP70 Autoantibody Formation by B-1 Cells inToxoplasma gondii-Infected Mice

“…Indeed, the sequence of TgHSP70 is 68.1 and 74.1% homologous to those of mouse HSP70 (mHSP70) and hHSC70, respectively (6,8,47,50); thus, it is possible that the high homology of HSP70 between T. gondii and hosts could induce autoreactive immune responses in T. gondii-infected hosts. Autoantibody induction against host components has been reported in infection with other parasites such as Trypanosoma cruzi (16), Plasmodium falciparum (21), Schistosoma mansoni (15), and Onchocerca volvulus (27). In particular, Mattei et al demonstrated that sera from humans infected with malaria recognized the human HSP70, indicating that autoantibodies directed against host HSP70 could be induced by the homologous parasite protein (21).…”