Innate & Adaptive Immunity

Vocabulary flashcards covering the distinctions between innate and adaptive immunity, protective barriers, humoral and cellular factors, and antibody functions based on the lecture transcript.

Innate Immunity

Also known as non-specific immunity; it provides a rapid response within hours, uses fixed (non-adaptive) mechanisms, and lacks immunological memory.

Adaptive Immunity

Also known as specific immunity; it is a delayed response (days) characterized by specificity, adaptiveness, memory, and the ability to discriminate between self and non-self.

Normal Flora

Microorganisms that live on or in the body (such as the skin, colon, and vagina) but do not cause disease, serving as a biological defense.

Lysozyme

A chemical defense enzyme found in tears, saliva, sweat, and mucus that breaks down bacterial components.

Interferons (IFNs)

Humoral factors involved in the second line of defense; including Type I ($IFN-\alpha$, $IFN-\beta$) with antiviral actions and Type II ($IFN-\gamma$) which enhances macrophage and $NK$ cell activity.

Complement System

A group of humoral factors activated via classical, MB-lectin, or alternative pathways resulting in opsonization, chemotaxis, and pathogen killing.

Opsonization

The process of coating a pathogen with substances like $C3b$ to enhance its recognition and ingestion by phagocytes.

Membrane Attack Complex (MAC)

A structure formed by complement components $C5-C9$ that creates transmembrane channels in a microbe's plasma membrane, leading to cytolysis.

Phagocytosis

A cellular process involving chemotaxis, adherence, ingestion, and digestion of microbes within a phagolysosome.

Antigen Presenting Cells (APCs)

Cells such as monocytes/macrophages, dendritic cells, and B cells that capture and present antigens to T lymphocytes.

Natural Killer (NK) cells

Innate immune cells that recognize and kill virus-infected cells and tumor cells.

Dendritic Cells

Cells that serve as a linkage between innate and adaptive immunity by capturing antigens at peripheral sites and presenting them in lymph nodes.

Humoral Response

The branch of adaptive immunity mediated by B lymphocytes and the production of antibodies ($IgG$, $IgE$, $IgD$, $IgM$, $IgA$).

Cell-mediated Response

The branch of adaptive immunity mediated by T lymphocytes, specifically $CD4^+$ helper cells and $CD8^+$ cytotoxic cells.

Primary Immune Response

The initial response to an antigen exposure, characterized by a latent period followed by a lower concentration of antibodies, starting with $IgM$.

Secondary Immune Response

The rapid and intense response upon re-exposure to an antigen, characterized by a high concentration of $IgG$ and minimal latent period.

Neutralization

An antibody function where the antibody prevents bacterial or viral adherence to host cells or neutralizes toxins.

Inflammatory Response

A second line of defense where damaged tissues release histamines, increasing blood flow and allowing phagocytes and clotting factors to reach the injured area.

SCID/CID

Classic primary immune deficiencies representing a lack of function or primary immune defects.

Cytotoxic T lymphocyte (CTL)

A type of T cell that recognizes microbial antigens presented by MHC I and kills infected cells.