University Of Central Florida | PCB 3233 Immunology | Exam 4 Practice Questions with ANSWERS 2025/2026

University Of Central Florida | PCB 3233 Immunology | Exam 4 Practice Questions with ANSWERS 2025/2026 Exam 4 Practice Questions NOTE: This sheet should only serve as a study aid for Exam 4. Although this was approved by Professor Weigel, it may contain errors, so please use other resources, such as Panopto Videos and the PowerPoints, to best prepare yourself for the exam. DO NOT expect these exact questions on the exam, as they were created by me using the PowerPoints. 1) All of the following are true about T-cell development except: A. T-cells derive from bone marrow stem cells B. T-cells undergo gene rearrangement that lead to formation of Ag receptors C. T-cells divide into two lineages D. T-cells are activated in the thymus T-cells mature in the thymus and are activated in secondary lymphoid tissues (lymph node, MALT, spleen, Peyer’s patches) 2) True or False: The major function of the thymus is to ensure that the T-cells that leave it are restricted to the particular MHC class expressed by an individual person. 3) What is the main difference between positive and negative selection for T-cells? A. Positive selection leads to the death of immature T-cells, while negative selection leads to death of mature T-cells B. Positive selection leads to the death of mature T-cells, while negative selection leads to the death of immature T-cells C. Positive selection leads to the death of immature T-cells that do not interact with any selfMHC molecules, while negative selection leads to the death of immature T-cells that interact strongly with self-MHC molecules D. Positive selection leads to the death of immature T-cells that interact strongly with selfMHC molecules, while negative selection leads to the death of immature T-cells that do not interact with any self-MHC molecules 4) Why do only 1-2% of a:b T-cell primary repertoire exit the thymus? A. Somatic recombination B. Positive selection C. Negative selection D. A, B, & C 5) Immature thymocytes are mostly found in the ____, while mature thymocytes are mostly found in the ____ A. Cortex; Medulla B. Medulla; Cortex C. Cortex; CortexD. Medulla; Medulla 6) All of the following are true regarding DiGeorge’s Syndrome except: A. This results from a deletion in chromosome 22 B. This causes the thymus to fail in its development C. This syndrome resembles SCID D. All of the above are true This syndrome negatively affects your adaptive immunity… NO T-cells being developed… no B-cell activation 7) True or False: The thymus grows larger and more efficient as one progresses through life. It shrinks and becomes less efficient… won’t really affect you because 1) T-cells are self-renewing and 2) T-cells are longer lived… Thymectomy (thymus removed) also won’t negatively affect your immunity 8) What is the main role of a Notch-1 receptor? A. Keeps a B-cell on the correct path for differentiation B. Keeps a T-cell on the correct path for differentiation… Notch-1 receptor is located on thymocyte, while Notch-1 ligand is located on the thymic epithelial cell… this interaction takes place up until the thymocyte becomes single-positive (look @ slide 35 on Ch. 7) C. Keeps an NK-cell on the correct path for differentiation D. Keeps all lymphocytes on their respective path for differentiation 9) What are the four different signals given by a pre-TCR? Pre-TCR à pre-T-alpha (or p-t-alpha), beta chain, CD3 complex, and two zeta chains 1) Allelic exclusion… we are going to turn off RAG-1 and RAG-2 for the beta chain (stops rearrangement of other beta chains) 2) Proliferation (of the beta chain) 3) Expression of CD4 and CD8 (we go from a double negative thymocyte to a double positive thymocyte at the pre-TCR stage) 4) Turn on RAG-1 and RAG-2 for rearrangement of the alpha chain Successful pre-TCR à when it forms a superdimer Pre-TCR is considered checkpoint 1 in T-cell development 10) True or False: About 2% of thymocytes fail to make a productive rearrangement, which results in their death through apoptosis. 98% actually fail 11) True or False: MHC uses somatic recombination to gain diversity in their binding site. Polymorphism!!! Diversity across the population12) Select all that apply: What forms a pre-TCR? A. Rearranged b-chain B. Surrogate a-chain C. Pta D. CD3 proteins E. z chain 13) Select all that apply: Once a pre-TCR is formed, what is it responsible for? A. Triggering thymocyte proliferation B. Halting b-chain rearrangement C. Ensuring only one type of T-cell receptor b-chain is expressed by the T-cell D. .Recognizing antigen presented by MHC 14) How many potential attempts are allowed for successful b-chain rearrangement? A. 1 B. 2 C. 3 D. 4… 2 per loci, 4 per cell 15) Successful rearrangement of a b-chain induces the expression of ____ and ____, which terms the thymocyte “double positive” A. CD34; CD44 B. CD2; CD5 C. CD4; CD8 D. A, B, & C 16) Checkpoint 1 in TCR development ensures that we have a functional ____ chain, while checkpoint 2 in TCR development ensures that we have a functional ____ chain A. b; a B. a; b C. Heavy; light D. Light; heavy 17) True or False: Positive selection takes place in the cortex of the thyroid and is mediated by cortical epithelial cells. Occurs in the cortex of the THYMUS18) All of the following are true except: A. A T-cell can change the specificity of the TCR it expresses B. Once a T-cell is positively selected, rearrangement of the b-chain stops… beta chain rearrangement stops at the pre-TCR stage C. Some double positive thymocytes can express two a chains D. The number of positively selected cells is very small E. All of the above are true 19) Central tolerance for B-cells is seen in the ____, while central tolerance in T-cells is seen in the ____ A. Bone marrow; bone marrow B. Bone marrow; thyroid C. Bone marrow; thymus D. Bone marrow; periphery 20) What is negative selection primarily mediated by? A. Bone marrow-derived dendritic cells B. Bone marrow-derived macrophages C. Bone marrow-derived NK cells D. A & B… Dendritic cells and macrophages are both Profession-Antigen Presenting Cells (P-APCs) E. A, B, & C 21) True or False: AIRE is used to create self-peptides that are normally only found in the periphery. 22) What is FoxP3? A. Transcriptional repressor used by TH1 B. Transcriptional repressor used by TH2 C. Transcriptional repressor used by TFH D. Transcriptional repressor used by Treg… you don’t see a fox on the regular (credit Dom) 23) True or False: In this class, AIDS is defined as having less than 200 CD8 T-cells per microliter. Less than 200 CD4 T-cells per microliter, NOT CD8 24) All of the following are false except: A. The immune system initiates the adaptive immune response wherever a pathogen creates a site of infection B. Dendritic cells are stationary cells C. Dendritic cells carry Ags to primary lymphoid tissues/organs D. The major function of dendritic cells is to trigger T-cell responsesE. All of the above are false 25) True or False: MALT is part of GALT. GALT, RALT, BALT all fall under MALT 26) What receptor helps mediate endocytosis of antigens? A. DC-SIGN in immature dendritic cells B. DC-SIGN in mature dendritic cells C. DEC 205 in immature dendritic cells D. DEC 205 in mature dendritic cells 27) What is the term used to describe when antigens are taken up by a cell engulfing extracellular fluid? A. Endocytosis B. Macropinocytosis C. Micropinocytosis D. Phagocytosis 28) True or False: Naïve T-cells enter lymphoid tissues via blood capillaries or from the efferent lymph. NOT efferent (exit), but afferent (arriving)… can also get in through HEV’s 29) What happens once a T-cell encounters a peptide:MHC complex that it can bind to? A. T-cell is retained in the lymph node B. T-cell is activated C. T-cell proliferates D. T-cell differentiates into effector T-cells 30) What draws naïve T-cells directly to a dendritic cell? CCL and CXCL = chemokine = cytokine… NOT all cytokines are chemokines A. CCL19… brings T-cell to secondary lymphoid tissue B. CCL21… brings T-cell to secondary lymphoid tissue C. CCL18… secreted by activated/mature dendritic cells (interdigitating reticular cell) D. A & B E. A, B, & C 31) ____ and ____ are chemokines that bind to ____ in T-cells to draw them into secondary lymphoid tissue A. CXCL19; CXCL21; CCR7 B. CCL18; CCL19; CCL7 C. CCL19; CCL21; CCL7 D. CCL19; CCL21; CCR732) S1p acts as a ____ to lead lymphocytes to the ____ lymphatics sphingosine-1-phosphate (KNOW THIS) A. Chemotactic molecule; afferent B. Chemotactic molecule; efferent C. Cytotoxic molecule; afferent D. Cytotoxic molecule; efferent 33) What binds to DC-SIGN to strengthen adhesion between a T-cell and an activated dendritic cell? A. ICAM-2 B. ICAM-3… DC-SIGN (found on mature dendritic cells) binds to ICAM-3 (adhesion molecule, Ig-superfamily member) C. CD2 D. LFA-1 34) What suppresses the expression of S1p receptors? A. Conformational change in ICAMs that causes higher affinity to LFA-1 B. Conformational change in L-selectin that causes higher affinity to CD34 C. Conformational change in LFA-1 that causes higher avidity to ICAMs D. Conformational change in LFA-1 that causes higher affinity to ICAMs 35) True or False: An intracellular signal generated by TCR:peptide:MHC complex interaction is sufficient for activation of that given naïve T-cell. NEED B7 (surface of dendritic cell) and CD28 (surface of T-cell) interaction to take place 36) The binding of ____ (on the T-cell) and ____ (on the APC) gives a costimulatory signal that completes the activation of a naïve T-cell A. B7; CD28 B. CD28; B7 C. B7; CD34 D. CD34; B7 37) B7 expression is a direct consequence of ____ A. Infection B. PRRs recognizing PAMPs C. Chemokines D. Cytokines38) All of the following are true regarding CTLA-4 except: A. Activated T-cells express this receptor B. CTLA-4 binds B7 twentyfold more strongly than does CD28 C. CTLA-4 functions as an antagonist D. CTLA-4 accelerates activation and cell proliferation it downregulates T-cell activation/proliferation E. All of the above are true 39) True or False: Dendritic cells, macrophages, and B-cells are termed “professional APC’s” that can activate naïve T-cells. P-APCs à dendritic cells, B-cells, and macrophages… however, ONLY dendritic cells can activate naïve T-cells (due to them having a high expression of B7) 40) True or False: p-SMAC allows for the clustering of receptors-co-receptors and signaling molecules. p-SMAC à adhesion molecules… c-SMAC à TCR, co-receptors, CD3 complex 41) List the signaling pathway that takes place as a result of TCR and co-receptor clustering. 1) TCR:peptide:MHC interaction 2) Lck (kinase) phosphorylates ITAMs 3) ZAP-70 will bind to ITAMs and become phosphorylated Lck 4) ZAP-70 activates PLC-gamma 5) PLC-gamma cuts PIP2 into DAG and IP3 6) Transcription factors (NFkB, NFAT, AP-1) are activated 7) IL-2 is produced… leads to proliferation of T-cells… also have cell division and differentiation taking place 42) What drives the proliferation and differentiation of activated T-cells? A. IL-1 B. IL-2 C. IL-3 D. IL-4 43) Naïve T-cells express the ____ receptor for IL-2, which consists of ____ chains A. Low affinity; a, b, and g B. High affinity; a, b, and g C. Low affinity; b and g D. High affinity; b and g 44) Activated T-cells express the ____ receptor for IL-2, which consists of ____ chains A. Low affinity; a, b, and g B. High affinity; a, b, and g C. Low affinity; b and gD. High affinity; b and g 45) What happens when a naïve T-cell binds to a peptide:MHC complex on an APC that does not express B7? A. T-cell undergoes peripheral tolerance B. T-cell becomes nonresponsive/anergic C. T-cell begins producing/secreting IL-2 D. A & B E. A, B, & C 46) True or False: Anergic T-cells still produce IL-2, meaning they can proliferate and differentiate. 47) True or False: CD8 T-cells differentiate into 5 subclasses, these being TH1, TH2, TH17, TFH and Treg cells. CD4 T-cells actually differentiate into the 5 subclasses, CD8 T-cells are simply cytotoxic and don’t differentiate any further 48) All of the following are false except: A. IL-12 and IFN-g are the transcription factors for TH1 cells… these are the characteristic cytokines B. GATA3 is the cytokine that induces differentiation of a CD4 T-cell into a TH2 cell… this is the transcription factor C. IL-17 is the characteristic cytokine secreted by TH17 cells D. TH2 cells secrete IL-4 to activate B-cells that make IgM… IgE, NOT IgM E. All of the above are false 49) List all types of CD4 effector T-cells (provide function) Th1 à activate macrophages by secretes IFN-gamma, leads to inflammation at site of infection Th2 à fights parasitic infections (through IgE, basophils, eosinophils, mast cells) Th17 à recruits neutrophils to site of infection TFH à aids in activation of B-cells (found in follicle of secondary lymphoid tissues) Treg à immune suppressor (downregulates) 50) True or False: CD4 T-cells can help activate naïve CD8 T-cells as long as they recognize antigen on different APCs. Has to be the SAME APC for this to occur 51) Cytotoxic CD8 T-cells and TH1, TH17, Treg CD4 T-cells are expected to be found in the ____, while TFH and TH2 are expected to be found in the ____ A. Sites of infection; primary lymphoid tissues B. Sites of infection; secondary lymphoid tissues C. Sites of infection; lymph nodes D. Sites of infection; sites of infection52) What adhesion molecule is highly expressed in naïve T-cells and not expressed in effector Tcells? A. LFA-1 B. CD2 C. L-selectin D. ICAM-1 53) Effector T-cells express ____, which enables binding to endothelial cells of blood vessels in infected/inflamed tissues A. CTLA-4 B. VLA-4 C. LFA-4 D. ICAM-4 54) True or False: All chemokines are cytokines. 55) In cytokine signaling, what is used to promote phosphorylation? A. Notch-1 B. Notch-1 ligand C. JAKS… Janus Kinases D. STATS 56) In cytokine signaling, what serves as a transcription factor? A. Notch-1 B. Notch-1 ligand C. JAKS D. STATS… Signal Transducers and Activators of Transcription JAKS phosphorylates STATS, which will dimerize and enter the nucleus for transcription of the cytokine genes 57) True or False: The function of cytotoxic CD8 T-cells is to kill cells that have become overwhelmed by extracellular infection. INTRAcellular infections 58) All of the following are true except: A. Secretion of IFN-g inhibits the replication of viruses in the infected cells B. IFN-g increases the processing and presentation of bacterial antigen by MHC class I molecules… MHC I processes intracellular (viral) antigens… bacterial antigens are extracellular C. IFN-g activates macrophages in the vicinity of the cytotoxic T-cellsD. All of the above are true 59) ____ is death due to physical or chemical injury in which cells lyse and disintegrate, while ____ is death in which cells shrivel or shrink but remain intact A. Apoptosis; necrosis B. Phagocytosis; necrosis C. Necrosis; apoptosis D. Necrosis; phagocytosis 60) True or False: Apoptosis prevents the replication and release of infectious pathogens. 61) What directs cytotoxins into the cytoplasm of an infected host cell? A. Perforin B. Granulysin C. Serglycin D. Granzymes 62) What activates apoptosis by activating caspases in the host cell? A. Perforin B. Granulysin C. Serglycin D. Granzymes 63) True or False: The second signal for macrophage activation is delivered by the CD40 ligand (CD40L) present on the surface of a macrophage. CD40L is located on the T-cells… CD40R is located on the macrophage… B-cells can also express CD40 (slide 95) 64) What lymphocyte has mild-staining granules? A. Basophils B. Eosinophils C. Neutrophils D. None of the above 65) What are our lymphocytes? A. B-cells B. T-cells C. NK-cells D. ILC’s E. A, B, & C F. A, B, C, & D66) True or False: All lymphocytes are leukocytes, not all leukocytes are lymphocytes. 67) Say you score the following in the first 5 exams: 100, 88, 92, 100, 70. Will you need to take the final to score an A in this class? A. Yes B. No 68) What is the preferred method of communication with Professor Weigel and/or the TAs? A. Email on Canvas B. Email on Knights Email C. Text D. Call