Immunity To Bacterial Disease

Host defense ● Host defenses may be: ● Innate immunity. ● Acquired immunity. ● Innate immunity: ▪ Physical barriers: Intact skin, mucous membrane. ▪ Phagocytic cells: Neutrophil, macrophage, NK cell. ▪ Others: Complements, lysozyme, interferon, gastric acid, fatty acid of skin, cilia in mucosa.

Host defense ● Acquired immunity: ▪ Antibody mediated. ▪ Cell mediated: T cell, B cell, Macrophage, dendritic cell. ● Acquired immunity may be two types: ▪ Active immunity ▪ Passive immunity

Classification of Immunity

The Immune System ▪ Components of innate or acquired.

Acquisition of Acquired Immunity Can be acquired naturally or artificially: 

Natural acquisition — person acquires immunity through natural means: Active & Passive.



artificial acquisition — person is given something that results in immunity: Active & Passive.

Acquisition of Acquired Immunity A.Naturally acquired active immunity: Antigens

or

pathogens

enter

body

naturally. Body

generates an immune response to antigens.

Immunity

may be lifelong (chickenpox or mumps) or temporary (influenza).

Acquisition of Acquired Immunity B. Naturally acquired passive Immunity: Antibodies

pass from mother to fetus via placenta or breast feeding (colostrum).

No

immune response to antigens.

Immunity

is usually short-lived (weeks to

months). Protection

develops.

until child’s immune system

Acquisition of acquired immunity 1. Artificially acquired active immunity: Antigens are introduced (immunization).

in

vaccines

Body generates an immune response to antigens. Immunity can be lifelong (oral polio vaccine) or temporary (tetanus toxoid).

Acquisition of Acquired Immunity 2. Artificially acquired passive immunity: Preformed antibodies (antiserum) are introduced into body by injection: ATS or TIG. Immunity is short lived.

Innate & Adaptive Immune response

Adaptive immunity

Innate immunity

Microbes Structur al Barriers

NK Cells

Chemical Barriers Killing of microbes and infected cells

Phagocytes TLRs

Granulocytes

Complement

Immunoglobulins

T Cells B Cells

Innate & Adaptive Immune response Microbes

NK Cells

Chemical Barriers Killing of microbes and infected cells

Adaptive immunity

Phagocytes TLRs

T Cells

Immune regulatio

Complement

Antigen processing & presentation B Cells Kill infected Euk. cells

Granulocytes

Immunoglobulins

Specific Immune

Innate immunity

Structur al Barriers

Bacterial Vaccine 

Bacterial may give active or passive immunity:

● Active immunity: Capsular polysaccharide vaccine: Strept. Pneumoniae, H. influenzae. Toxoid vaccine: Cl. Tetani, B. pertussis. Purified protein vaccine: B. pertussis, B. anthracis.

Bacterial Vaccine Live attenuated bacterial vaccine: M. tuberculosis, S. typhi. Killed bacterial vaccine: V. cholerae, Yersinia pestis. ● Passive immunity: Antitoxin against tetanus, Botulinum, Diphtheria.

Quote of the day

“Why leave the tail……. ….if you ate the rest of the cow.”

CTL activating macrophage function

CD8+ T and CD4+ T

Opsonization 1.

Opsonizing antibodies may enhance phagocytic clearance of viral particles.