Viruses in autoimmune disease

Viruses have been found to be associated with the presence of autoimmune disease in humans and other animals. They may cause autoimmune disease by a number of different mechanisms including polyclonal activation of lymphocytes (e.g. Epstein-Barr virus), release of intracellular organelles due to destruction of

8 cell stimulated by major determinant oil foreign Ag Same epitope is expressed on .self-Ag

8 cell stimulated by major determinant oil foreign Ag Same epitope is expressed on .self-Ag

Foreign Ag Major epitope
Self-Ag Cross-reacting epitope

^P^ Ab binds epitope on foreign Ag

A I) also binds epitope1 on self-Ag

Figure 5.5 The role of antigen mimicry in autoimmune disease

If the major antigenic determinant of an infectious agent is similar antigenically to a self-antigen, then the response elicited by the microorganism can result in an autoimmune response.

^P^ Ab binds epitope on foreign Ag

A I) also binds epitope1 on self-Ag

Figure 5.5 The role of antigen mimicry in autoimmune disease

If the major antigenic determinant of an infectious agent is similar antigenically to a self-antigen, then the response elicited by the microorganism can result in an autoimmune response.

host cells, antigen mimicry (Figure 5.5; Table 5.6), induction of abnormal MHC Class II antigen expression and functional impairment of immunologically regulatory cells, e.g. T suppressor cells.

Role of Epstein-Barr virus in autoimmune disease: Epstein-Barr virus (EBV) infects B cells and directly causes their activation. Although some autoreactive B cells escape elimination in the bone marrow, they are usually prevented from producing autoreactive antibody either by a lack of antigen-stimulated T cell help or by T cell-mediated suppression. However, if a potentially autoreactive B cell is infected by EBV it can proliferate and differentiate into a plasma cell without the help of T cells. Infected cells from both healthy individuals and patients with rheumatoid arthritis secrete polyclonal IgG and IgM anti-immunoglobulin antibodies (rheumatoid factor) but B cells from patients produce more, higher affinity antibody than those from normal persons.

Was this article helpful?

0 0
Arthritis Relief Now

Arthritis Relief Now

When you hear the word arthritis, images of painful hands and joints comes into play. Few people fully understand arthritis and this guide is dedicated to anyone suffering with this chronic condition and wants relief now.

Get My Free Ebook


Post a comment