Micro Chapter 18

Adaptive Immunity

A learned response that recognizes specific antigens and provides targeted defense against pathogens.

B Lymphocytes

B cells that produce antibodies targeting extracellular pathogens.

T Lymphocytes

T cells that mediate cellular immunity and can destroy infected cells.

First Line of Defense

Innate barriers that include physical, chemical, and genetic barriers to prevent pathogen entry.

Second Line of Defense

Includes phagocytosis, interferons, and the complement response to combat pathogens.

Third Line of Defense

Acquired immunity involving a targeted response from B and T lymphocytes.

Epitopes

Specific parts of antigens recognized by receptors on B and T cells.

Antigen-Presenting Cells (APCs)

Cells that process and present antigens to activate T lymphocytes.

Major Histocompatibility Complex (MHC)

A set of molecules on cell surfaces that help present antigens to T cells.

Immunogenicity

The ability of a substance to provoke an immune response.

Cytokines

Proteins secreted by T cells to recruit and activate other immune cells.

Phagocytosis

The process by which certain cells engulf and digest pathogens.

Neutralization

The action of antibodies to prevent pathogens from entering host cells.

Opsonization

The process of marking pathogens for phagocytosis.

Agglutination

Clumping of pathogens together for more effective clearance by the immune system.

Complement Activation

A process that triggers a series of immune responses to fight infections.

Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC)

Mechanism where antibodies recruit immune cells to destroy infected cells.

Active Immunity

Immunity acquired through exposure to an antigen or vaccination.

Passive Immunity

Immunity acquired through transfer of antibodies, such as maternal antibodies.

Vaccination

A method of stimulating the immune system to provide protection against diseases.

Herd Immunity

Increased immunity in a population that reduces disease spread and protects non-immunized individuals.

IgG

The most abundant class of antibodies, providing the majority of antibody-based immunity.

IgM

The first antibody produced in response to an infection.

IgA

An antibody found in mucosal areas, providing protection against pathogens.

IgE

An antibody associated with allergic responses.

IgD

An antibody with an unclear function, found on immature B cells.

Helper T Cells (CD4)

T cells that orchestrate both humoral and cellular immunity.

Cytotoxic T Cells (CD8)

T cells that destroy infected or foreign cells.

Clonal Selection Theory

The mechanism by which undifferentiated lymphocytes undergo divisions to create specific receptors.

Self vs Non-Self Recognition

The ability of the immune system to distinguish between its own cells and foreign substances.

Memory Cells

Cells that remain after an immune response, providing rapid response upon re-exposure to an antigen.

Haptens

Small molecules that are non-immunogenic unless attached to a larger carrier.

Interferons

Proteins that inhibit viral replication and enhance the immune response.

Complement Response

A series of proteins that get activated to enhance the immune response against pathogens.

Stem Cells

Undifferentiated cells that give rise to various blood cell types.

Bone Marrow

The site of maturation for B lymphocytes.

Thymus

The site of maturation for T lymphocytes.

Antigen

Any substance that induces an immune response.

Cell-Mediated Immunity

Immune response mediated by T lymphocytes that target infected cells.

Humoral-Mediated Immunity

Immune response characterized by antibody production from B lymphocytes.

Antibody Structure

Composed of two heavy chains and two light chains.

Plasma Cells

B cells that produce and secrete antibodies after activation.

T Cell Receptor (TCR)

A molecule on T cells that binds processed antigens on MHC molecules.

B Cell Receptor (BCR)

A membrane-bound immunoglobulin on B cells that binds free antigens.

Superantigens

Substances that can trigger excessive immune responses by activating many T cells.

Antibody Functions

Includes neutralization, opsonization, agglutination, and complement activation.

Lymphocyte Development

The maturation and differentiation of B and T cells in response to antigens.

Immunocompetence

The ability of B and T cells to mount an effective immune response.

Myeloid Cells

Blood cell types derived from myeloid stem cells, including erythrocytes and leukocytes.

Lymphoid Cells

Blood cell types derived from lymphoid stem cells, including T cells, B cells, and NK cells.

Growth Factors

Proteins that influence the differentiation of stem cells into various blood cell types.

Erythrocytes

Red blood cells responsible for oxygen transport.

Neutrophils

A type of white blood cell that engulfs pathogens.

Basophils

A type of white blood cell involved in inflammatory responses.

Monocytes

White blood cells that differentiate into macrophages and dendritic cells.

Platelets

Cell fragments involved in blood clotting.

Cytotoxic Effects

The ability of certain immune cells to induce cell death in infected or abnormal cells.

Vaccine Types

Includes live attenuated, killed, and subunit vaccines.

Transplant Compatibility

The ability of MHC molecules to ensure acceptance of transplanted tissue.

Disease Transmission

The spread of disease from one individual to another.

Adaptive Immune Response

The specific immune response that develops over time with exposure to antigens.

Infection

The invasion and multiplication of pathogenic microbes in the body.

Innate Immune Responses

Immediate, non-specific responses to pathogens upon first exposure.

Vaccination History

The historical development of vaccines from live pathogens to modern techniques.

Pathogen Clearance

The process of eliminating infectious agents from the body.

Immune System Regulation

The control of immune responses to ensure appropriate reactions to pathogens.

Pathogen Neutralization

The blocking of pathogen action by binding it to antibodies.

Enzyme Barriers

Chemical barriers that inhibit microbial growth and infection.

Acidity Barriers

Chemical defenses in the body, such as gastric acid, that destroy pathogens.

Skin as a Barrier

A physical barrier that protects against pathogen entry.

Mucous Membranes

Physical barriers that trap pathogens and prevent infection.

Genetic Barriers

Inherited traits that provide resistance to certain pathogens.