Immunity to infectious disease
ا . م . د وفاق محمود علي الوتارInfection could be:
Viral Bacterial Parasitic FungalTypes of immune response:
Non-specific immune response Mechanical: as Skin ,saliva ,tears, ciliary movement, mucus , Cellular :NK, macrophages ,complement lysis,commensals Specific immune response.The types of immune response
Cellular: Mediated by the lymphocytes and cytokines. Th-1,Th-2,Th-DelHumoral Mediated by antibodies like IgG ,IgM, IgE, IgA, IgD.
Immune response against bacteria
Cellular or humeral The function of ab could be Opsonizing Complement fixing Haemolysing Agglutinating Surface receptors as IgD Secretory IgAImmunity to viruses
Obligate IC pathogen Invasion ,replication, evasion of immune system. Antiviral response is a complex process Alpha ,beta, gamma INF,as 1ST two interfere with viral replication ,stimulate the MHC -1 to make it recognizable to T-LC ,and activate NK cells to kill infected cells By ADCC NK produce gamma INF----act macrophage Complement damage the envelope of some virusesRole of humoral immunity
Neutralizing antibodies IgG the most active combine with viral antigen on cell surface leading to ------attachment of NK,Macr,PMNs --- damage to viral infected cells ADCC IgA protect epithelial & mucosal surfaces Agglutination of viral particles IgM complement activation, promoting phagocytosis by macrophage Opsonization Inhibition of viral enzymesTYPES OF HOST INFECTION
Or locally as rhinovirus If there is entry local invasion---- followed by haematogenic spread----- target organ infection e.g measles ,poliomylitis hepatitis. Or local entry-----neurological spread e.g rabies. Some others remaine dorminant as HSV Some are latent as HIV ,CMV,EBV.Cellular immune response
After infection cell mediated immunity is the main eliminator of virally infected cells CD4+,CD8+. CD4+--------effective antibody Cytokine production Excess macrophage activation CD8+ are generated early ,can recognize the virally infected cells +MHC 1Immunity to bacteria
G+ve Thick peptidoglycan Teichoic acid,CHO,protiens Resist cell lysis by complement IR: spesific Ab,opsonine,phagcytosis by PNC IgG,IgM, & OR C3b Cell wall stimulate alternative pathway---opsonine--- inflamatry IRG-ve Thin inner &outer cell membrane. LPS endotxines can directly activate the ulternative pathway C3aC5a--chemotactic C3b Spesific antibody Phagositic cells
Special bacteria
mycobacteriaspirochets
Immunity to parasites
Immunity to fungi
Bacterial evasion of immune responseCapsule Toxins Antigenic variation IC survival Immune system suppression Extacellular enzymes Expression of antibody binding protiens