Changes

==TH₁ Cells==

==TH₁ Cells==

[[Image:TH1-macrophage.jpg|thumb|right|150px|TH-1 cells boost macrophage response - B. Catchpole, RVC 2008]]

[[Image:TH1-macrophage.jpg|thumb|right|200px|TH-1 cells boost macrophage response - B. Catchpole, RVC 2008]]

*TH1 cells help macrophages digest bacteria (''organisms in vesicles'')

TH1 cells help macrophages digest bacteria - the organisms are contained in vesicles.

* TH₁ cells secrete a range of cytokines.

 

* Cytokines secreted include:

TH₁ cells secrete a range of cytokines, including:

** '''IL-2'''.

* '''IL-2''', which induces proliferation of both [[Helper CD4+|CD4+]] and [[Cytotoxic CD8+|CD8+ T-cells]]. This stimulation of T cell proliferation is the main function of the TH₁ cell.

*** Gives proliferation of both [[Helper CD4+|CD4+]] and [[Cytotoxic CD8+|CD8+ T-cells]].

* '''Interferon gamma''' ('''IFNγ''') which activates tissue macrophages and is the principal effector mechanism in the defence against intracellular bacteria and parasites such as Mycobacteria, Brucella, Rickettsia Leishmania, Coccidia, and Babesia. Interferon gamma activates macrophages and stimulates them to produce enzymes triggering intracellular killing mechanisms - specifically:

*** This stimulation of proliferation of [[T cells|T cells]] is the main function of the TH₁ cell.

#Superoxide dismutase and myeloperoxidase that produce H₂O₂ and trigger the "superoxide burst".

** '''Interferon gamma''' ('''IFNγ''').

#Nitric oxide synthase which produces nitric oxide.  

*** Activates tissue macrophages  

 

*** Is the principal effector mechanism in the defence against intracellular bacteria and parasites.

This is another example of the immune system working through the innate immune response - this can act to suppress antibody synthesis.

**** E.g. Mycobacteria, Brucella, Rickettsia (bacteria) and  Leishmania, Coccidia, Babesia (parasites).  

**** Activates macrophages and stimulates them to produce enzymes triggering the intracellular killing mechanisms, e.g.

***** Superoxide dismutase and myeloperoxidase.

****** Produce H₂O₂ and trigger the "superoxide burst".

***** Nitric oxide synthase.

****** Produces nitric oxide.  

**** This is another example of the immune system working through the innate immune response.

*** Can act to suppress antibody synthesis.

==TH₂ Cells==

==TH₂ Cells==