Lecture 7

Question 1

Lymphocytes (T-Cells, B-Cells, and Natural Killer Cells)

Answer 1

1. T-Cells: Cell-mediate Adaptive Immunity
2. B-Cells: Humoral Adaptive Immunity
3. NK Cells: Innate Immunity

Question 2

Lymphocytes

Answer 2

1. Cluster of differentiation marker
   —- Abs
2. Distinct CD proteins are differentially expressed in different
3. lymphocyte sub-populations as they undergo their lineage-specific differentiation

Question 3

B-Cells (Antibody-producing Lymphocytes)

Answer 3

1. Originally discovered in the Bursa of Fabricius in chicken

Question 4

B-Cells

Answer 4

1. Humans: B-Cells mature in the bone marrow
2. Part of the Adaptive Immune System
3. express B-Cell Receptors (BCR) on their surface
   — membrane-bound antibody
   — >100,000 BCR protein copies/B-cell
   — each individual B-Cell has a unique BCR clone
   — cam recognize soluble or particulate antigens

Question 5

B-Cells

Answer 5

1. Naïve B-Cells: Antigen Binding to BCR
   — results in plasma cells
2. Plasma Cells: Increased ‘protein production’ organelles

Question 6

T-Cells (Cell-Mediated Immunity)

Answer 6

1. Site of T-Cell maturation: Thymus
2. Part of the Adaptive Immune System
3. Express T-Cell Receptors (TCR) on their surface
   — each individual T-Cell has a unique TCR clone
   —- only recognize antigens presented on MHC proteins
4. Two major T-Cell types:
   a. T helper cells (TH)
   b. T cytotoxic cells (Tc)

Question 7

Educating Naïve TC-Cells

Answer 7

1. Requires Antigen Presenting Cell
2. TCR binds to MHC-antigen complex
3. Binding induces clonal proliferation
4. Binding induces differentiation cytotoxic T lymphocyte (CTL)

Question 8

Natural Killer Cells

Answer 8

1. Lytic Granules present in the cytoplasm
2. Originates from Lymphoid precursors
3. Part of the Innate Immune System
4. Detects and Targets “Abnormal” Cells
   a. Tumor Cells
   b. Virally-infected

Question 9

Natural Killer Cells: Absence of MHC Class 1

Answer 9

1. ‘Normal’ Cells: MHC I on their surface
2. NK Cells MHC I recognition: inhibits cytotoxic granule release
3. Lack of MHC I recognition: permissive for cytotoxic granule release