Humoral Immunity, Immunoglobulins, Complement

Vocabulary flashcards covering the key concepts of humoral immunity, immunoglobulins, complement, hypersensitivity, fever, and innate immune receptors as presented in the lecture notes.

Complement Steps

Recognition Unit

Activation Unit

Membrane Attack Unit

Antibodies for Complement

2 IgG or 1 IgM

End Result of Complement

lysis of a pathogenic cell

Immune Adherence Phenomenon

Process by which C3b-coated targets attract lymphocytes, PMNs, monocytes, and macrophages to enhance immune response

Antibody

A specific immunoglobulin that recognizes and binds an antigen.

Fc Fragment

The stem of the antibody made from the heavy chains; complement surface

Fab Fragment

Antigen-binding region of an antibody, composed of one light and one heavy chain variable domain.

Immunoglobulin Isotypes

5 heavy chains: IgG, IgA, IgM, IgE, IgD

2 light chains: kappa and lambda

Immunoglobulin (Ig)

A soluble antibody produced by plasma cells that binds antigens.

IgG

Major serum antibody (≈80% of Ig); crosses placenta and secreted in milk; activates complement; opsonizes.

IgA

Secretory antibody found in tears, saliva, gut/nasal secretions, and milk; includes secretory component and J chain.

IgM

Pentameric antibody; first antibody produced in primary response; strong complement activator.

IgE

Antibody involved in allergic responses and defense against parasites; facilitates release of histamine; binds mast cells, basophils, and eosinophils

IgD

Low-abundance antibody on B-cell surfaces; helps in antigen recognition and B-cell activation.

Most Abundant Ig

IgG

Ig Found in Breast Milk

IgG, IgA

Ig Activating Complement

IgM, IgG

Ig Crossing Placenta

IgG

Antigen

Substance that provokes an immune response; contains antigenic determinants (epitopes).

Anaphylactoxin

C3a and C5a

Secretory Antibody

IgA

Reagenic Antibody

IgE

Fever

Pyrexia; elevation of body temperature due to inflammation and pyrogens.

Pyrogen

Substance that induces fever; can be exogenous (microbes) or endogenous (cytokines).

Possible Causes of Fever

infection, cancer, autoimmune diseases, medications

Cancers Most Likely to Cause Fever

acute leukemias, lymphomas, renal cell carcinoma, hepatocellular carcinomas, primary brain tumors in the hypothalamus

Inflammatory Diseases Likely to Cause Fever

Autoimmune: systemic lupus erythematosus, rheumatoid arthritis, PAN

Granulomatous: sarcoidosis, Chron’s, giant cell arteritis

Drugs Likely to Cause Fever

most likely: antihistamines

others: antipsychotics, tricyclic antidepressants, monoamine oxidase inhibitors, cocaine, PCP, amphetamines, LSD

Miscellaneous Causes of Fever

malignant hyperthemia, neuroleptic malignant syndrome, hyperthyroidism, pheochromocytoma, environment

Systems to Investigate for Fever of Unknown Origin

respiratory, urogenital, skin and soft tissue

Production of Cytokines

toll-like receptors on the surface of macrophages detect pathogens, which trigger the release of cytokines; macrophages produce cytokines

Toll-Like Receptors (TLRs)

Innate immune receptors on macrophages/monocytes recognizing microbial components to trigger inflammation.