Immunity to infection &Immunomodulation and Vaccine

Immunity to infection

Microfold (M) cells

capable of transporting luminal antigens to the underlying lymphoid tissues

and can be exploited by pathogens as an entry portal to invade the host

Immune privilege sites

able to tolerate the introduction of antigens without eliciting an inflammatory immune response

Immune responses to intracellular bacteria

Innate immunity

- Secreted IL-2 by infected macrophage sense NK cell activation and secretion of IFN-g resulted in macrophage activation

- Activated macrophage demonstrated the increasing killing activity

Adaptive immunity

- Activation of T cell -> (mainly Th1) resulted in macrophage activation

Immune response against bacterial infection

Intracellular bacteria

- Neisseria gonorrhoeae
- Mycobacterium tuberculosis

Extracellular bacteria

-Staphylococcus aureus->Inflammation, Pus
-Gram –ve bacteria
-Ig production as neutralizing Abs

viral infection

- Obligate intracellular organism
- Specific receptor-ligands binding

Parasitic infection

Mechanical obstruction

- Ascaris lumbricoides or tapeworms->intestinal obstruction
- Filarial parasites->obstruct the flow of lymph through lymphatics

Physiologic effect

- Giardia spp. -> malabsorption
- Diphyllobotrium latum->pernecious anemia

Tissue damage

Immunomodulation and Vaccine

Immunomodulation

meaning

Modifying the immune response

Immunology of Vaccination

Protective immunity can be achieved
by active or passive immunization.

Comparison of Passive and Active Immunizations

Active or passive immunization

Produced actively by the host immune system

Passive immunization

Obtained passively,no participation

Vaccine

Classification

Whole-Pathogen Vaccines

Live-attenuated vaccines

a version of the living microbe that has been weakened
in the laboratory

Inactivated vaccines

Produced by killing the pathogen with chemicals, heat or radiation

Subunit Vaccines

Toxoid vaccines

Use a toxin (harmful product) made by the germ that causes
a disease.

Diptheria

tetanus

Polysaccharide vaccines

taken from the outside
layer of encapsulated bacteria

Conjugated vaccines

taken from the outside layer of encapsulated bacteria and join the molecules to carrier proteins

Recombinant vaccines

Produced through recombinant DNA technology

Hepatitis B virus (HBV)

human papillomaviruses (HPVs)

Developing vaccine in the future

DNA vaccines

DNA coding for a particular antigen

Recombinant vector vaccines

using a virus or bacterium from one disease essentially acts as a
delivery device for an immunogenic protein from another
infectious agent

Factors that Influence the Immune Response to Vaccination

express more MHC molecules that are part of the antigen (signal 1) that T cells recognize

increase the expression of costimulators (signal 2) and cytokines

stimulate migration of the DCs to lymph nodes where T cells are located