Volume 45, Issue 5
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



The presence of lytic antibodies in the circulation of patients with chronic Chagas' disease might lead to their cure. It has been shown that amastigotes of activate complement and accumulate large amounts of the terminal complement components, but without killing the parasites. One plausible explanation for this observation is that the insertion of the membrane attack complex of complement is prevented by inhibitors present in the parasite membrane. To explore this possibility, we raised a panel of monoclonal antibodies (MAbs) against the surface molecules of amastigotes. One of these, MAb M4C12, induced complement-mediated lysis of amastigotes as detected with a Rb-release assay. The antigen molecule from the membrane lysate of amastigotes that was recognized by MAb M4C12 was purified, characterized, and designated M4C12Ag. It is a 92-kD molecule structurally related to Ssp4, a previously characterized amastigote surface molecule. However, M4C12Ag is more basic (pI 6.9–7.1) than Ssp4 (pI 5.2–6.0), and is larger (92 kD) than Ssp4 (70 kD and 84 kD). Purified M4C12Ag did not inhibit the terminal components of complement when tested in hemolytic assays. This molecule may not be an inhibitor of complement, yet it is certainly an amastigotespecific surface molecule with immunologic importance because it is the only molecule that could induce formation of a lytic antibody.


Article metrics loading...

The graphs shown below represent data from March 2017
Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error