BT501 Final Term Slides

UMAIR SALEEM

 The adaptive immune system is basically a defense system in the human body that remembers the entry and action of each and every pathogen

 Adaptive immune response is antigen specific and needs the recognition of specific antigens during antigen presentation

 The special adaptive capability of immune cells is maintained in the body by memory cells.  The lymphocytes belong to the adaptive immune system.

 There are two different types of lymphocytes, B cells and T cells.

 These · cells · are · generally · derived

from hematopoi-etic stem cells in the bone marrow.

 B cells take part in the humoral immune response, while T cells are mainly involved in cell-mediated immune response.  Both B and T cells contain receptor molecules that distinguish specific targets.  For example, T cells recognize a pathogen only after antigens are processed and presented in combination with major histocompatibility complex (MHC) molecule.

Types of T-cells

 3 types

 Stimulate Cytotoxin T-cells Cytotoxin T-cells Kill virally Infected Cell  Suppressor T-cells  Suppress further killing of cells

T-Cells · Killer T cells · Killer T cells

• Killer T cells are a subtype of T cells that can either kill cells that are infected with viruses and pathogens, or make them dysfunctional.
• It has been shown that killer T cells are acti-vated when T cell receptor binds to antigens of another MHC cell
• The recogni-tion of this MHC–antigen complex is aided by a coreceptor localized on the T cell, which is also called CD-8.