Immunity

Innate

What immunity system do the first two lines of defense fall under?

IgM

Which antibody class is the primary antibody, a potent agglutinating agent, and activates complement?

IgA

Which antibody class is in mucus membranes, saliva, tears, and breast milk?

IgE

Which antibody class is active in some allergies and parasitic infections and causes mast cells + basophils to release histamine?

IgD

Which antibody class is attached to B cells and functions as B cell receptors?

IgG

Which antibody class makes up 75-85% of antibodies in plasma, forms secondary and late primary responses, and can cross the placental barrier?

Phagocytes, fever, complement, interferons, NK cells

What components are in the 2nd line of defense?

2nd line

Which line of defense includes inflammation?

Leukocytes and macrophages exposed to foreign substances secrete pyrogens, body temp is raised via hypothalamus, liver and spleen sequester iron and zinc to raise metabolic rate

What is the pathophysiology of fever?

Chemical release, vasodilation and increased vascular permeability, and phagocyte mobilization

What are the stages of the inflammatory response?

Bradykinin, histamine, & prostaglandins cause vasodilation and leaky capillaries

What happens during the chemical release stage of the inflammatory response?

RBC, WBCs, and platelets lead to swelling, redness, heat, and pain

What happens during the vasodilation & increased vascular permeability stage of the inflammatory response?

Neutrophils attracted via chemotaxis squeeze through blood vessel walls (extravasation)

What happens during the phagocyte mobilization stage of the inflammatory response?

Cytokines

Which proteins are chemical messengers of the immune system that mediate cell development, differentiation, and immune response by causing inflammation?

Cytokines

What larger protein class do interferons, interleukins, and TNF fall under?

Enhance innate defense via direct attack, prohibiting microorganisms from reproducing

What do antimicrobial proteins like interferons and complement proteins do?

Family of immune modulating proteins, cells infected with viruses can secrete IFNs to warn neighboring cells

What are interferons?

Enter neighboring cells and stimulate production of proteins that block viral reproduction and degrade viral RNA, and activate NK cells and macrophages

How do interferons help with the immune system?

Cascade of 20 blood proteins leading to destruction of foreign substances, both innate and adaptive

What is complement?

Enhances inflammation and directly destroys microorganisms

What does complement do?

Classical (Adaptive)

Which complement pathway is antibody active and more specific to the isolated germ of infection?

Alternative (Innate)

Which complement pathway binds directly to the foreign antigen?

When the MAC inserts into the cell membrane and causes influx of water and lysis of the microorganism

When does cell lysis begin in the complement system?

Complex of four complement proteins that bind to plasma membrane of pathogens

What is the Membrane Attack Complex (MAC)?

Neutrophils, macrophages, and dendritic cells

What are the three main types of phagocytes?

Neutrophils

Which phagocyte is most abundant and dies fighting?

Macrophages

Which phagocyte develops from monocytes and are the chief phagocytics?

Dendritic Cells

Which phagocyte is abundant in skin and mucus membranes?

Non-phagocytic granular lymphocytes in blood and lymph

What are NK cells?

Create pores in target cells for chemicals to enter and kill via apoptosis, and secrete cytokines to cause inflammation

How do NK cells kill tumor and virus cells before the adaptive immune system?

B lymphocytes produce antibodies in the plasma/blood and lymphatic fluid, antibodies bind to target cell to mark it for destruction

What is humoral immunity?

T lymphocytes act against target cell and provide defense against intracellular antigens (virally infected cells, cancerous/abnormal cells, foreign/transplanted cells)

What is cellular immunity?

Cytoxic (Direct action) and chemical release (Indirect, Helper T)

What are the two types of T lymphocytes?

T and B cells learn to recognize antigens

What is immunocompetence?

T and B cells learn not to kill their own cells

What is self-tolerance?

Type IV cytotoxic T cell hypersensitivity response

Which hypersensitivity response is initiated by graft v. host?

Cyclosporin (IL-2 inhibitor) and Methotrexate (T cell apoptosis)

What is the treatment for graft v. host?

T cells

Which cell type requires antigen-presenting cells?

Original antigen brought into APC, fragment of original antigen is presented on MHC molecule

How to antigen-presenting cells work?

Macrophages & dendritic cells (phagocytes) and B lymphocytes (receptor-mediated endocytosis)

What are some examples of MHC molecules?

Set of genes that encode cell surface proteins and allow for recognition of self/non-self antigens, basis behind graft rejection

What is a Major Histocompatibility Complex?

Contain groove that can hold piece of self antigen or foreign antigen and alerts immune cell if antigen belongs to body or not

How do MHCs work?

Class I

What MHC molecule type is displayed by all cells except RBCs?

Class I

What MHC molecule type displays these messages?

If APC: I belong to self but kill anything that looks like this

If not APC: I belong to self, but something invaded me, so kill me

Which MHC molecule type is only on APCs and displays this message?

I belong to self, help me amount an immune response to this antigen

Antibodies/Immunoglobulins

What are described as proteins secreted by plasma cells, capable of binding with antigens?

Antibodies/Immunoglobulins

What immune system component doesn't destroy antigens, but inactivates and tags them?

Complexes

What do antibodies form with antigens?

Opsonization, agglutination, complement fixation, and neutralization

What are the main defensive mechanisms of antibodies?

Opsonization

In which defense mechanism are antigens inundated with antibody molecules?

Agglutination

In which defense mechanism do antibodies bind to the same receptor on two different antigens at the same time?

Neutralization

In which defense mechanism do antibodies block specific sites on viruses or bacterial exotoxins, preventing them from binding to tissue cells?

They undergo phagocytosis

What happens to complexes during neutralization?

Complement Fixation

In which defense mechanism do several antibodies bound on the same antigen align complement-binding sites on their stem regions?

MACs and cell lysis

What happens in complement fixation when complement binds to antibodies?

Complement Fixation

What is the main defense mechanism for cellular antigens like bacteria and mismatched RBCs?