Exam 2 Chp. 4: Adaptive Immunity

Flashcards covering key vocabulary and concepts from Adaptive Immunity.

Adaptive Immunity

Characterized by specificity for individual microbes, memory of prior exposures, and enhanced responses to repeated exposures.

Innate Immunity

Includes the body's barrier defenses, phagocytic cells, and soluble factors.

Thymus

The central organ responsible for T-cell maturation and education.

T Cell Receptor (TCR)

A membrane-bound receptor composed of two protein chains that recognizes short peptide fragments on MHC molecules.

CD4 Marker

A marker found on helper T cells that stabilizes TCR and MHC class II interactions.

CD8 Marker

A marker found on cytotoxic T cells that stabilizes TCR and MHC class I interactions.

Positive Selection

Ensures that developing T cells can recognize self-MHC molecules; cells failing to bind die by neglect.

Negative Selection

Eliminates T cells that bind too strongly to self-antigens to prevent autoimmunity.

Cytotoxic T Cells

CD8+ T cells that recognize antigens presented on class I MHC molecules and induce apoptosis in target cells.

Class I MHC Molecules

Present endogenous peptides to CD8+ T cells, enabling surveillance of infected or abnormal cells.

Class II MHC Molecules

Present exogenous peptides to CD4+ T cells, initiating helper responses.

Pro-B Cell

The initial stage of B-cell development in the bone marrow where heavy-chain gene rearrangement begins.

Plasma Cell

Fully differentiated B cell that produces large amounts of antibodies.

Memory T Cells

Long-lived T cells that respond quickly upon re-exposure to an antigen.

Memory B Cells

B cells that can rapidly differentiate into plasma cells upon re-encountering the same antigen.

Flow Cytometry

A technique used to analyze cell surface markers and distinguish different T and B cell populations.

Humoral Immunity

The production of antibody by plasma cells.

Autoreactive T Cells

T cells that can attack the body's own tissues, prevented by negative selection.

Haptens

Substances that are immunogenic only when coupled to a protein carrier.

Haplotype

One set of six HLA genes inherited from one parent.

CD3 Marker

An identifying marker for T cells that appears at the first stage of T cell development.

Germinal Centers

Locations in lymph nodes where B cells undergo affinity maturation and class switching.

Intracellular Pathogens

Pathogens like viruses that replicate inside host cells.

Extracellular Pathogens

Pathogens found outside of host cells, such as bacteria.

Cytokines

Signaling proteins secreted by T cells that influence the immune response.

Which MHC molecule is necessary for antigen recognition by CD4+ T cells?

class 2

Which would be characteristic of an immune response to a T-independent antigen?

antigen are often polysaccharides

humoral immunity refers to which of the following

production of antibody by plasma cells 

Where does antigen-independent maturation of B lymphocytes take place?

bone marrow

In the thymus, positive selection of immature T cells is based upon recognition of which of the following?

MHC antigens

Which of these is/are found on a mature B cell?

IgM and IgD

How do cytotoxic T cells kill target cells?

They produce granzymes that stimulate apoptosis

Which of the following can be directly attributed to antigen-stimulated T cells?

cytokines

Which is a distinguishing feature of a pre-B cell?

U chains in the cytoplasm

When does genetic rearrangement for coding of antibody light chains take place during B-cell development?

as the cell becomes an immature B cell

Which of the following marker is found on “helper” T cells?

CD4

Which of the following would represent a DN thymocyte?

CD3+CD4–CD8–

Which of the following best describes the TCR for antigen?

α and β chains are unique for each antigen

Laboratory results belonging to a 3-year-old patient showed the following: normal CD4+ T-cell count, normal CD19+ B-cell count, low CD8+ T-cell count. Which aspect of immunity would be affected?

Elimination of virally infected cells

Which of the following is a unique characteristic of adaptive immunity?

Ability to remember a prior exposure to a pathogen

Clonal deletion of T cells as they mature is important in which of the following processes?

elimination of autoimmune responses

where are germinal centers found

in lymph nodes

Substances that are immunogenic only when coupled to a protein carrier are:

haptens

MHC class I proteins include:

HLA-A, HLA-B, HLA-C

Which MHC class of antigens is necessary for antigen recognition by CD4+ T cells?

MHC class II

Adjuvants act by which of the following methods?

protects antigens from being degraded

When a child inherits ONE set of six HLA genes together from one parent, this is called a(n):

haplotype

Which cluster of differentiation (CD) marker appears during the first state of T cell development and remains present as an identifying marker for T cells?

CD3

T lymphocytes that possess the CD8 surface marker mediate which of the following functions?

cytotoxic

T lymphocytes that possess the CD4 surface marker mediate which of the following function(s)?

helper and regulatory

What is the order of the steps involved in T cell differentiation? DP=double positive, DN=double negative, SP=single positive

DN to DP to SP

T cell maturation occurs in the

thymus