How big is this antigen differs in the sizes of other published cross-reactive antigens, including B13 (8), ribosomal proteins (12, 29), Cha (15), cruzipain (13), and Fl-160 (41)

How big is this antigen differs in the sizes of other published cross-reactive antigens, including B13 (8), ribosomal proteins (12, 29), Cha (15), cruzipain (13), and Fl-160 (41). the lack of detectable cardiac harm. may be the protozoan parasite that triggers Chagas’ cardiovascular disease (CHD), a fatal cardiomyopathy leading to dilated tissues potentially. 16 million folks are contaminated with this protozoan parasite Around, and 120 million are in risk of an infection in Central and SOUTH USA (28). CHD develops in one-third of an infection of human beings and experimental pets roughly. The queries are (i) whether this autoimmunity is normally pathogenic and (ii) with what system(s) autoimmunity is normally induced. The issue surrounding this matter is normally long-standing (analyzed in personal references 17, 22, 39, and 40). an infection induces humoral and mobile autoimmunity to a different group of autoantigens (analyzed in personal references 17 and 22), including cardiac myosin. Myosin-specific autoimmunity is normally induced in both human beings (8) and experimental versions (24) upon an infection. In previous function (24), it had been discovered that within weeks of an infection, A/J mice acutely infected with developed serious myocarditis accompanied by myosin-specific delayed-type hypersensitivity antibody and (DTH) creation. Autoimmunity to cardiac myosin continues to be reported for various other cases of cardiac harm also, including those taking place due to viral an infection (32), cardiac transplantation (11), and cardiac medical procedures (9). Taken jointly, this information shows that cardiac harm can result in the introduction of cardiac autoimmunity with a bystander activation system where cardiac harm in the correct setting can switch on autoreactive lymphocytes (21). Nevertheless, there are a variety of reports supporting the theory that a molecular mimicry mechanism is responsible for the development of autoimmunity. Immunization with proteins, in the absence of live parasites, can induce autoimmunity to self-antigens. Immunization of mice with cruzipain induces growth of T cells and B cells specific to skeletal Dihydromyricetin (Ampeloptin) myosin (13) and autoantibodies to cardiac myosin (14), and immunization of mice with ribosomal proteins induces autoantibodies to mammalian ribosomal proteins (30). Finally, T-cell clones reactive with both myosin and the B13 protein have been isolated from the hearts of humans with CHD (7). To further investigate whether antigens could induce cardiac autoimmunity in CHD, we tested whether immunization of mice with an extract of in complete Freund’s adjuvant (CFA) could induce autoimmunity to the major cardiac autoantigen, cardiac myosin. The extract was produced by using acetone; thus, parasite proteins and no viable parasites were present in the immunogen. We found that mice immunized with this extract developed significant myosin-specific DTH and antibodies, even though the mice did not develop myocarditis as a result. Equally important, immunization of mice with cardiac myosin induced and myosin is usually bidirectional. These results suggest that cardiac damage is not required for the induction of myosin autoimmunity by and that, in the setting of live contamination, both bystander activation and antigenic cross-reactivity may contribute to the development of cardiac myosin autoimmunity. MATERIALS AND METHODS Mice, parasites, and contamination protocol. Four- to six-week-old male A/J and C57BL/6 mice (Jackson Laboratories, Bar Dihydromyricetin (Ampeloptin) Harbor, Maine) were housed under specific-pathogen-free conditions. epimastigotes were produced at 26C in supplemented liver digest-neutralized tryptose (LDNT) medium as Dihydromyricetin (Ampeloptin) described previously (18). promastigotes (clone LV 78) were maintained in medium 199 (Gibco BRL, Grand Island, N.Y.) supplemented with 10% heat-inactivated fetal bovine serum (Gibco BRL) and produced at 25C (27). Mice were infected by intraperitoneal injection of 104 Brazil strain trypomastigotes derived from contamination of tissue culture H9C2 rat myoblasts (American Type Culture Collection, Manassas, Va.). Uninfected controls received an intraperitoneal injection of Dulbecco’s phosphate-buffered saline (PBS; Gibco BRL) of equal volume. Mice were anesthetized by a single intraperitoneal injection of sodium pentobarbital (60 mg/kg of body weight) for each experimental manipulation. Mice were used and cared for in accordance with the guidelines of the Center for Comparative Medicine at Northwestern University. Antigens. Cardiac myosin heavy chains were purified from syngeneic hearts, and skeletal myosin heavy chains were purified from syngeneic quadriceps muscles according to the method of Shiverick et al. (36) with modifications as described previously (24). For immunizations, and antigens were CHUK prepared by washing epimastigotes or promastigotes three times in PBS and resuspending them in PBS before addition of an equal volume of acetone for extraction. After being washed three times in PBS, these.