11- Immunology X, XI, XII Flashcards
Is the class of immunity induced of significance to the host?
Yes the induction of an exclusive cell-mediated response results in limited disease, whereas induction of a humoral or mixed-cell response results in a chronic or fatal course
What is humoral immune deviation?
Induction of an antibody to an antigen precludes attempts to induce cell-mediated immunity in form of delayed-type hypersensitivity (DTH) to this antigen by a course of immunization
The response in locked in a humoral mode
What is cell-mediated immune deviation?
The induction of a cell mediated response that precludes the induction of antibody, immune response to antigen is locked in cell mediated mode
What happens to mice unresponsive for the induction of Delayed-type hypersensitivity? (DTH)
After induction of antibody to antigen they contain in their spleen, T cells, that when given to normal animals, prevent the induction of DTH to this antigen by an immunized protocol that is normally successful
Example on page 43
What are clones of T cells?
When a precursor cell is induced it multiples to produce a clone of cells
It’s possible to stimulate a single precursor cells in presence of growth hormone of T cells (IL2)
So one T cell stimulated with antigen in presence of IL2 will produce around a million identical cells
What are cytokines?
Molecules secreted by CD4+ T cell clones when they are stimulated with phagocytic cells
They are delivered to target cells by producing cell binging to target cell with its receptor
Either positively or negatively regulate growth and differentiation of other cells
Do different T cells secrete different cytokines?
Yes
What is IFNγ?
How is it related to macrophage activation?
It is a cytokine that can prevent viral multiplication and its delivery to infected macrophages by protein-specific CD4T cells can result in macrophage activation
What are the cytokines IL4 and IL10’s roles?
Humoral immunity
IL4 increases IgG and IgE responses
IL4 and IL10 favours induction of humoral, Th2 responses
What is similarity of Th1 and Th2?
Cell mediated Th1 immune responses
Th2 antibody responses
Cell mediated Th1 response in mouse produced against a parasite can be abrogated by giving it antibodies that bind to and inactivate IFNγ and a Th2 response occurs instead (can be vice versa)
picture on page 45
Why do most people never get allergic?
They produce IgG antibodies rather than IgE antibodys to common allergens
Producing IgE antibody decreases IgE response and enhances IgG response
(Allergy treatment)
What an approach for treatment of autoimmunity using IgA?
Deviate the immune response against the self-antigen, and responsible for the autoimmune pathology into IgA mode so that it is harmless
What is the cell mediated way of vaccines against infectious diseases?
Immunization by locking the immune response to subsequent exposures to the pathogen into cell-mediated mode
The hope is these will work in people
What does the induction of CD4+ T cells require?
Interaction between phagocytic cell bearing the MHC class II molecule-peptide complex and the T cell This reaction is mediated by a molecule called B7 on macrophage and CD28 molecule on T cell
Why are organ grafts rapidly rejected?
Because the grafts co twin donor macrophage-like cells that bear both the graft antigens and B7
NOT because cells are immunogenic
