Effects of Anti-Endothelial Cell Antibodies in Leprosy and Malaria

Abstract

As a result of damaging endothelial cells (ECs), Mycobacterium leprae triggers the production of antibodies (Abs). These anti-EC Abs (AECAs) can be divided into two types. The first type nonspecifically reacts with components of the cytosol (CY) and can be detected by enzyme-linked immunosorbent assay (ELISA). The second specifically reacts with the EC membrane (MB) and requires fluorescence-activated cell sorter (FACS) analysis to be detected. The presence of both types of AECAs was determined in 68 leprosy patients. The ELISA was positive for 35 of them but also for 30 of 34 malaria patients and 17 of 50 healthy African controls. However, whereas FACS analysis showed MB reactivity in only three malaria patients and four controls, this reactivity was found in 27 leprosy patients, more of those having the lepromatous than the tuberculoid form. Specificity for MB, which we failed to absorb by incubation with CY lysates, predominated over that for CY in leprosy, unlike malaria, where the EC reactivity was restricted to the CY. Western blot analysis and twodimensional electrophoresis revealed that calreticulin, vimentin, tubulin, and heat shock protein 70 were targeted by AECAs from leprosy patients, but other proteins remained unidentified. These auto-Abs, but not those from malaria patients, did activate ECs, as indicated by the E-selectin and intercellular adhesion molecule 1 upregulation, and/or induced them into apoptosis, as documented by four different methods. Our findings suggest that, in some but not all leprosy patients, AECAs may play a role in pathogenesis.

Blood coagulation in falciparum malaria—a review

“…Occasionally, malaria parasites have been found inside the platelets ) but they are most likely to be transient passengers rather than source of infection to platelets. Body usually mounts an intense immune response to malaria parasite per se; in addition, the proteins from malaria parasite acts as universal B cell mitogen leading to production of widespread antibodies against autoantigens leading to false positive serology for many antigens (Dugue et al 2004;Pradhan et al 2002). Thus, production of antiplatelet antibodies and immune complex formation followed by immune absorption onto platelets are other additional mechanisms which cause thrombocytopaenia in malaria (Biswas 1999;Tyagi and Biswas 1999).…”

Anti-alpha-actinin antibodies are part of the anti-cell membrane antibody spectrum that characterize patients with lupus nephritis

“…Based on our previous study showing that flow cytometry was effective for exploring anti-MbA and that differences exist between cell types [22], the kidney-derived cell line HEK was selected to examine IgG anti-MbA. As shown in Fig.…”

Sera of patients with systemic lupus erythematosus react with plasmodial antigens and can inhibit thein vitrogrowth ofPlasmodium falciparum

“…Antiphospholipid antibodies are most common, either associated with infection or as an independent autoimmune phenomenon [40]. The rather unspecific anti-cytosol-protein antibodies are reported in malaria and leprosy, although the more specific anti-endothelial membrane antibodies are restrained to the latter [41]. Specificity of auto-Ab may also be related to the degree of immunity in malaria.…”