01817nas a2200265   4500000000100000008004100001260001300042653001200055653003100067653001000098653001700108653001900125653001000144653001100154653002100165653002200186653001200208653002500220100001400245245003700259300001000296490000700306520122400313022001401537       1991                            d  c1991 Nov10aAnimals10aAntibodies, Anti-Idiotypic10aBirds10aHIV Antigens10aHIV Infections10aHIV-110aHumans10aImmune Tolerance10aImmunosuppression10aleprosy10aMycobacterium leprae1 aDohms J E00aMechanisms of immunosuppression.  a19-300 v303 a<p>Immunosuppresive disease is a major economic concern in domestic poultry production. Although many immunosuppressive agents have been described, mechanisms of how infectious and noninfectious agents compromise the immune system are poorly understood in avian species. Two categories, generalized and antigen-specific immunosuppression have been described in mammals. Generalized immunosuppression produces overall reduced responsiveness and increased susceptibility to a wide variety of infectious and neoplastic diseases. The best characterized immunosuppressive mechanisms are described in HIV-1 infections that lead to acquired immune deficiency syndrome (AIDS) in humans. In contrast, the antigen-specific suppression observed in human leprosy illustrates how an infecting agent selectively suppresses host responses against itself favoring bacterial spread. Both diseases have well-defined clinical staging classifications that correlate with specific immunological defects. An approach to studying immunosuppressive mechanisms in the avian suggests the need for relating pathogenesis with tests of immune responsiveness using a series of increasingly more specific immunological assays to pinpoint defects.</p>  a0165-2427