Immune System pt 3

These flashcards cover the essential vocabulary related to T cell functions and antibody actions, helping students understand key concepts for their exam.

Cytotoxic T cells (CD8+)

T cells that directly recognize and kill infected or abnormal cells displaying foreign antigens on Class I MHC molecules.

Apoptosis

A form of programmed cell death induced by cytotoxic T cells to eliminate virus-infected and tumor cells.

Regulatory T cells (TReg)

T cells that maintain immune tolerance and suppress excessive immune activation.

Helper T cells (CD4+)

T cells that coordinate the adaptive immune response and are essential for B cell activation.

Cytokines

Signaling molecules released by T cells and other immune cells that amplify the immune response.

Interleukin-1 (IL-1)

A cytokine released by macrophages to promote T cell activation.

Interleukin-2 (IL-2)

A cytokine secreted by activated T cells that drives T cell proliferation.

Clonal expansion

The process by which activated T cells proliferate to create a large number of identical effector T cells.

Major Histocompatibility Complex (MHC)

Proteins that display antigen fragments on cell surfaces for T cell recognition.

Class I MHC proteins

These proteins are present on nearly all nucleated cells and present antigens to CD8+ T cells.

Class II MHC proteins

Proteins found only on professional antigen-presenting cells (APCs) that present antigens to CD4+ T cells.

Antigen-MHC complex

A combination of an antigen and MHC molecule recognized by T cell receptors (TCRs).

T cell receptor (TCR)

A molecule on the surface of T cells that recognizes and binds to specific antigens presented by MHC.

Co-stimulation

An additional signal required for T cell activation beyond antigen binding.

Anergic

A state in which a T cell becomes unresponsive and fails to activate.

Antigen-antibody complexes

Complexes formed when antibodies bind to antigens, marking them for destruction.

Extracellular pathogens

Pathogens that exist outside of host cells, targeted by antibodies.

Monoclonal antibodies

Antibodies that are identical and produced by a single clone of B cells, specific to one antigen.

IgE antibodies

A class of antibodies important for the defense against parasitic infections, particularly worms.

Eosinophils

White blood cells that bind to IgE antibodies and release toxic substances to destroy parasites.

Complement fixation

The process where antibodies bind antigens and activate the complement system to promote cell lysis.

Agglutination

The clumping of cells or particles due to the binding of antibodies to multiple antigens.

Precipitation

The formation of soluble antigen-antibody complexes that can precipitate out of solution.

Neutralization

The process by which antibodies block the binding sites of toxins and pathogens, preventing infection.

Plasma B cells

B cells that produce antibodies after differentiating from activated B cells.

IgM antibodies

The first class of antibodies produced in response to an antigen; a pentamer that is a potent agglutinating agent.

IgA antibodies

A class of antibodies found in secretions like mucus that helps prevent pathogen entry.

IgG antibodies

The most abundant type of antibody in serum, typically involved in secondary immune responses.

Antibody classes

The five major classes of antibodies: IgM, IgA, IgD, IgG, and IgE, each with distinct functions.

Variable regions (V regions)

Parts of antibodies that bind specific antigens, formed from the combination of heavy and light chains.

Heavy chains

The larger polypeptide chains in antibody structure that determine the antibody class.

Light chains

The smaller polypeptide chains in antibody structure that combine with heavy chains to form the antibody.

Antigen-binding sites

Specific regions on antibodies formed by variable regions that recognize and bind to antigens.

Gamma globulin

The fraction of blood serum containing immunoglobulins (antibodies).

Hybridomas

Cell hybrids formed from the fusion of a tumor cell and an antibody-producing B cell.

Clinical homeostatic imbalance

A state where normal immune function is disrupted, often leading to disease.

Immune response

The coordinated reaction of the immune system to the presence of antigens.