Molecular mimicry to look like self. Certain Bacteriodes species produce a surface antigen similar to gut mucosa. Certain E. coli serotypes produce surface antigens similar to ABO blood groups 3. Genetic factors - mice with the lyt locus are resistant to infection by Salmonella typhimurium . Probably related to major histocompatibility group.
Resistance infers another state which is sensitive.
Effects of prenatal exposure to antigen 5. Molecular mimicry can aid in the establishment of a resident state but also might lead to an autoimmune response. B. Immune suppression - hormonal interactions with the immune system . High concentrations of hormones such as testosterone and progesterone and steroids have immunosuppressive effects. D. Antigenic variation E. Proteases - IgA protease of Neisseria Lesions may result from inflammation due to an infection and may be the primary symptom in the disease.