TABLE 2-5.

Mechanisms of Cell and Tissue Damage Produced by Micro-organisms

Mechanism	Examples
DIRECT DAMAGE BY MICRO-ORGANISMS
Production of toxins	See Table 2-6
Production of enzymes	Proteases, coagulase, DNAses produced by Staphylococcus aureus
Apoptosis	HIV (CD4+ T cells); Shigella spp. (macrophages)
Virus-induced cytopathic effects: Cell enlargement and lysis Formation of syncytium	Cytomegalovirus Respiratory syncytial virus
Inclusion bodies:
Intracytoplasmic Nuclear	Rabies Herpesviruses
Transformation	Human papillomavirus type 16
DAMAGE VIA THE HOST IMMUNE RESPONSE
Cytotoxic T cells and natural killer lymphocytes	Production of the measles rash, hepatitis A
Autoimmunity	Acute rheumatic fever, Streptococcus pyogenes
Immediate hypersensitivity	Rashes associated with helminth infections
Cytotoxic hypersensitivity	Cell necrosis induced by hepatitis B
Immune complexes	Glomerulonephritis in subacute endocarditis
Delayed type hypersensitivity	Tuberculous granuloma, caseous necrosis