Immunology

C1 inhibitor deficiency is associated with hereditary angioneurotic oedema Deficiencies in C1 C2 and C4 components are associated with systemic lupus erythematosus and other collagen vascular diseases Deficiency in C3 and its regulatory protein causes recurrent pyogenic infections Deficiency in C5 C6 C7 C8 and C9 components results in bacteremia mainly with Gram-negative diplococci and toxoplasmosis

IgG protects the body fluids IgA protects the body surface IgM protects the blood stream IgE mediates reaginic hypersensitivity

The clonal selection theory explains that individual lymphocytes are selected and proliferate upon encountering an antigen producing antibodies specific to that antigen

C1q is the first component of the classical complement pathway that binds to the antigen-antibody complex initiating the complement cascade

IgG is the most abundant immunoglobulin in the human body and plays a key role in the immune response particularly in defending against bacterial and viral infections

The immune response follows the sequence Internalized antigen is digested by the cell Altered self-cell presents the antigen T cell receptors then recognize the antigen bound to MHC and finally the antigen-MHC complex activates T cells

The sequence of phagocytosis starts with the bacterium becoming attached to the pseudopodia followed by ingestion phagosome-lysosome fusion and finally bacterial destruction by lysosomal enzymes

The correct sequence of the inflammatory response is the release of mediators followed by leakage of fluid and cells migration of phagocytes and finally the phagocytes and exudate destroy bacteria