Differential changes in heat shock protein-, lipoarabinomannan-, and purified protein derivative-specific immunoglobulin G1 and G2 isotype responses during bovine Mycobacterium avium subsp paratuberculosis infection

Bovine paratuberculosis is caused by infection of young calves with Mycobac terium avium subsp, paratuberculosis, In some of the chronically infected c ows the long asymptomatic stage (2 to 4 years) is followed by a rapid progr ession to a clinical stage due to protein-losing enteropathy, which will ul timately be fatal. The current dogma is that in early stages of disease the cell-mediated responses predominate, whereas in the clinical stage of the disease the humoral responses prevail, possibly signaling a switch in immun e reactivity related to disease progression. We developed immunoglobulin M (IgM)-, IgA-, and IgG1- and IgG2-isotype-specific enzyme-linked immunosorbe nt assays for M, avium subsp, paratuberculosis-derived antigens (heat shock proteins of 70 kDa [Hsp70] and 65 kDa [Hsp65], lipoarabinomannan [LAM], an d M. avium subsp. paratuberculosis purified protein derivative PPD [PPDP]), The serological responses of cows in different stages of paratuberculosis were used to evaluate the putative shift in immune responsiveness, In the c linical stage the PPDP-specific IgG1 responses were increased compared to t hose in the asymptomatic stage. However, total IgG1 and IgG2 and the Hsp70- , Hsp65-, and LAM-specific isotype responses were decreased in the clinical stage were decreased compared to those in the asymptomatic stage of diseas e. Thus, the classical pattern was found only for PPDP antigens and the IgG 1 isotype, For other antigens and isotypes and the total IgG levels, the re sponse pattern is different and indicates that there is no uniform associat ion with increased antibody responses during the progression from the asymp tomatic stage to the clinical stage of bovine paratuberculosis.