Immunity, Hypersensitivity, and Autoimmune Disorders

Vocabulary flashcards generated from lecture notes on immunity, hypersensitivity types, transplant rejections, congenital and acquired immune disorders, and HIV/AIDS.

Antigens

Foreign cells or substances that invade the body and are recognized as non-self.

Memory (Immune System)

The immune system response to the presence of an antigen due to previous exposure to that antigen.

Specificity (Immune System)

The principle that a specific lymphocyte will only respond to the presence of a specific antigen.

Self-Recognition

The ability of the immune system to recognize foreign material from the host ("self vs. non-self").

Passive Immunity

Immunity acquired through the injection of serum with ready-made antibodies from humans or animals (artificial) or acquired by babies from their mother's antibodies via the placenta (natural).

Active Immunity

Immunity developed through catching a disease or exposure to an antigen/immunization, in which the individual synthesizes specific antibodies.

Innate Immunity

In-born resistance to foreign substances that functions with no immune response.

Adaptive Immunity

Immune system mechanisms that distinguish host antigens from invader antigens, acting rapidly, specifically, destructively, and with memory to give long-term immunity.

Humoral Immunity

B lymphocyte immunity (also known as B cell immunity) that involves antibody production.

Cell-Mediated Immunity

T lymphocyte immunity (also known as T cell immunity) involving direct cellular responses.

Lymphocytes

The main cells of the immune response that are extremely specific and recognize only one specific antigen.

Helper T Cells (CD4 Cells)

Direct attacker T cells that turn on the immune system and stimulate the production of other T cells.

Suppressor T Cells

T cells that inhibit the immune response and block ongoing effects of the immune system to provide self-limiting effects.

Cytotoxic T Cells (CD8 Cells)

T cells that destroy cell membranes or secrete toxic substances to destroy non-self cells, such as cancer cells, transplanted organs, and grafted tissues.

B Lymphocytes

Bone-derived lymphocytes that produce antibodies that attack antigens.

Plasma Cells

B lymphocyte derivative cells that secrete immunoglobulins.

Memory Cells

B lymphocyte derivative cells that function in acquired immunity and act immediately upon re-exposure to the same antigen.

Natural Killer Cells

Surveillance cells of the immune system.

Vaccine

A weakened virus with disease genes removed or an injection of antibodies that causes the body to build specific immunoglobulins without causing disease.

Immunodeficiency

A state in which the body does not activate in the presence of an antigen, leaving it vulnerable to disease.

Hypersensitivity

An altered immune response to an antigen that results in harm to the client due to overpresentation of the inflammatory response.

Type 1 Hypersensitivity (Immediate)

An IgE-mediated response causing histamine release along with leukotrienes and cytokines that produce bronchiole smooth muscle constriction and edema.

Type 2 Hypersensitivity (Cytotoxic)

An immediate IgG or IgM reaction caused by transfusion/drug reactions or Rh incompatibility, leading to blood cell lysis or hemolysis.

Type 3 Hypersensitivity (Immune)

A reaction caused by the formation of IgG or IgM antigen-antibody complexes that adhere to walls of vessels, joints, heart, and other organs, resulting in conditions such as serum sickness.

Type 4 Hypersensitivity (Delayed)

A cell-mediated reaction producing delayed results within 24 to 48 hours after exposure, seen in poison ivy, TB skin tests, and transplant rejections.

Hyperacute Rejection

Organ transplant rejection that occurs 2 to 3 days following transplantation.

Acute Rejection

The most common and treatable type of organ transplant rejection, occurring from 4 days to 3 months post-transplant.

Chronic Rejection

Organ transplant rejection occurring 4 months to years post-transplant, leading to ischemia in the transplanted tissue.

Autoimmune Disorders

Conditions where the body attacks itself via autoantibodies, leading to chronic inflammation, tissue damage, and periods of remission and relapse.

Severe Combined Immunodeficiency (SCID)

A congenital disorder involving stem cell failure in which both T cells and B cells are absent.

DiGeorge Syndrome

A congenital immunodeficiency disorder characterized by T-cell failure.

Selective IgA Deficiency

A congenital immunodeficiency disorder characterized by B-cell failure.

Human Immunodeficiency Virus (HIV)

A retrovirus carrying genetic information in RNA format that targets helper T cells, alters host RNA transcription to read like DNA, and causes generalized immune deficiency.

Acquired Immune Deficiency Syndrome (AIDS)

An advanced HIV infection stage characterized by a CD4 count below $200\,\text{cells}/\mu\text{l}$ and the onset of opportunistic conditions.

ELISA / Western Blot Test

Diagnostic blood tests used to detect antibodies formed against the HIV virus.

HIV RNA Level Test

A measurement of viral load that serves as the earliest test to detect an HIV infection.

Window Period

The time frame from contraction of the HIV virus to antibody development, during which the patient is seronegative and tests negative on the HIV antibody test.

Sero-conversion

The transition from antibody-negative status to antibody-positive status, which on average occurs between 2 weeks and 6 months after infection.