Lymph, lymphatic vessels, lymph nodes, and other secondary lymphatic tissues and organs
Fluid and cells in lymphatic vessels
collect and return interstitial fluid to blood, transport immune cells throughout body, and transport lipid form intestine to blood
kidney shaped organs at intervals along lymphatic vessels
Lymphocytes and the lymph nodes
Naive lymphocytes are mature but haven't found antigen. They Circulate between blood, lymph and secondary lymph nodes. Lymphatic vessels pick up pathogens from infected tissue sites and arrive at the closest lymph node. T and B cells are at specific regions of nodes. Shape and size of nodes change in response to activation of lymphocytes.
Lymphocytes and the spleen
spleen is a lymphoid organ. It removes damaged or old erythrocytes and activates lymphocytes from blood borne pathogens. Red pulp removes erythrocytes and white pulp stimulates secondary lymphoid tissue.
2 primary portals of entry for pathogens
respiratory tract and gastrointestinal tract
What are the 2 Secondary lymphoid tissues?
Bronchial-associated lymphoid tissue (BALT) and Gut-associated lymphoid tissues (GALT) which are tonsils, adenoids, appendix, peyer's patches.
The innate immune response is initiated by what?
phagocytes, natural killer cells, and soluble proteins llike cytokines
Cells specialized in phagocytosis. Macrophages are in tissues and recruit neutrophils. Neutrophils enter infected tissues in large numbers. They recognize common molecules of BACTERIAL cell surface using a few surface receptors.
Inflammatory response enhances phagocytosis through what?
acute phase proteins
3 acute phase proteins and their functions
Mannose-binding lectin (MBL) binds to bacterial surface with particular spatial arrangement of mannose or fucose. C-reactive protein binds to phosphorylcholine on bacterial surface. Complement is a set of proteins which bind to bacterial surface
accumulation of fluid and cells at infection site. Swelling, redness, heat and pain.
The adaptive immune response
makes millions of different B and T cells for specific antibody-mediated and cell-mediated immunity
Antibody-Mediated Immunity (AMI)
involves B lymphocytes, plasma cells and antibodies. AKA humoral immunity
Cell-Mediated Immunity (CMI)
Involves T lymphocytes, antigen presenting cells and major histocompatibility complex (MHC) molecules. AKA cellular immunity.
Antibody-mediated Immunity is directed against
extracellular microorganisms and toxins.
B-lymphocytes (B cells) in AMI
differentiate into plasma cells which produce antibodies. They function as antigen-presenting cells.
Cell-mediated immunity is directed against
intracellular microorganisms. Both non-phagocytic cells and phagocytic cells
T-lymphocytes (T cells) in CMI
differentiate into effector cells following antigen presentation by antigen presenting cells
Functional types of T cells (3)
Helper (CD4 T cells) which are TH1 and TH2 cells. Cytotoxic (CD8 T cells). Regulatory (CD4 and CD8 Tregs)
molecule which stimulates production of and binds specifically to an antibody
Difference between antigen and immunogen
immunogens can stimulate an adaptive immune response while antigens can't. Best immunogens have a MW > 10,000
What are 3 potential antigens/immunogens
Carbohydrates, nucleic acids and lipids
Hapten. One example
Contemporary Immunology: A small antigen unable to elicit immune response but when combined with a larger carrier molecule, together they form an adaptive immune response. Example is Penicillin G with Albumin.
glycoproteins. cane exist as monomers, dimers, or pentamers of basic structure. Basic structure has 4 polypeptide chains. 2 identical light and 2 identical heavy chains.
Antibodies are secreted form of
IG made by plasma cells
antigen binding molecules of B cells.
Five classes of immunoglobulin Isotypes
IgA IgG IgM IgD IgE. IgM and IgE lack the hinge region
Explain the path of B lymphocytes
Originates and matures in bone marrow, then migrates to secondary lymphoid tissue where it is exposed to antigens. Then, it differentiates into plasma and memory cells. The plasma cells produce antibodies of all IG classes.
What do B lymphocytes do when antibody producing cells are activated in clonal selection?
B lymphocytes recognize intact pathogenic microorganisms and toxins. The B lymphs have specific surface receptors for recognition of antigens IgM and IgD. The binding results in proliferation of a clonal population of cells. The antigen determines clonal proliferation.
Proliferation of activated cells is followed by differentiation into
plasma cells who's life span can be 4-5 days or 1-2 months and memory cells that, when stimulated by an antigen, differentiate into plasma cells. Memory cells have a life span of years to decades.
Primary Antibody Response
after exposure to an antigen, there is a slow rise in IgM, followed by a slow rise in IgG.
Secondary Antibody Response
AFter exposure to previously encountered antigen, there is a rapid rise in IgG and slow or no rise in IGM.
Immune Response to Dengue Fever
The primary response is to make a small amount of IgM int he first couple days, then the memory cells take over and there is a rapid rise in IgG.
T lymphocytes origin/migration to
originate from stem cells in bone marrow then migrate to thymus gland, where they mature then migrate to secondary lymphoid tissue. They respond to antigens on the surface of antigen presenting cells.
Antigen presenting cells
macrophages, dendritic cells, B lymphocytes. They ingest and process antigens then display fragments on their surface in association with molecules of MHC
Major histocompatibility molecules. Class I present antigens to CD8 T cells. Class II present antigens to CD4 T cells. T cells that encounter antigen differentiate into effector T cells
Name 3 effector T cells in Immune Response
CD8 cytotoxic T cells, CD4 TH1 helper T cells, CD4 TH2 helper T cells
CD8 cytotoxic T cells
effector t cells that enter bloodstream and travel to infection site. kills cells infected with VIRUSES and other intracellular microorganisms. (Once activated to effector state, they leave secondary lymphoid tissue and kill the bad stuff)
CD4 TH1 helper T cells
enter blood stream and travel to infection site. Help activate MACROPHAGES
CD4 TH2 helper T cells
work within secondary lymphoid tissues and help activate B cells
Prevention of Hepatitis B
Vaccination with hepatitis B surface antigen HBsAg
Post-exposure protection against Hepatitis B
Administration of Hepatitis B Globulin Human, which is purified IgG antibody from plasma of donors with high titer of antibody to the hepatitis B surface antigen.
Treatment for Rheumatoid Arthritis
Using Remicade (infliximab) IgG kappa monoclonal antibody against tumor necrosis factor- alpha (TNF-alpha)
Treatment against Breast Cancer
Herceptin (trastuzumab) IgG kappa monoclonal antibody against human epidermal growth factor recepter 2 (HER2)