MHC & AG Processing Presentation Quiz

MHC-II molecules are found on the surface of antigen-presenting cells (APCs) such as macrophages, dendritic cells, and B lymphocytes. These cells are responsible for presenting antigens to CD4 T lymphocytes. CD4 T lymphocytes recognize antigens that are presented by MHC-II molecules, and they play a critical role in coordinating the immune response by activating other immune cells. Therefore, CD4 T lymphocytes are the target of MHC-II-restricted antigen presentation. CD8 T lymphocytes, on the other hand, recognize antigens presented by MHC-I molecules.

CD8 T lymphocytes are the target of MHC-I-restricted antigen presentation. MHC-I molecules present antigens derived from intracellular pathogens or abnormal self-proteins to CD8 T cells. This interaction triggers the activation of CD8 T cells, leading to the elimination of infected or abnormal cells. CD8 T lymphocytes play a crucial role in cell-mediated immunity and are responsible for killing virus-infected cells, tumor cells, and cells expressing foreign antigens.

The correct answer is Proteasome. Proteasomes are responsible for degrading proteins into peptides. These peptides are then transported into the endoplasmic reticulum, where they bind to MHC-I molecules and are presented on the cell surface for recognition by cytotoxic T cells. This process is known as MHC-I-restricted antigen presentation. Phagolysosomes, Golgi, peptidase, and nuclease are not directly involved in this process.

Patients with bare lymphocyte syndrome are most likely to be vulnerable to all types of pathogens, including viruses, intracellular bacteria, extracellular protozoans, and extracellular bacteria. This syndrome is characterized by a deficiency in major histocompatibility complex (MHC) class I and class II molecules, which play a crucial role in the immune response against various pathogens. Without functional MHC molecules, the immune system is unable to effectively recognize and eliminate different types of pathogens, making patients susceptible to a wide range of infections.

There are six possible MHC-I alleles that can be present on the cell surface of a normal, healthy individual.

Phagolysosomes are the source of peptides involved in MHC-II-restricted antigen presentation. Phagolysosomes are formed when phagosomes, which are membrane-bound vesicles containing engulfed pathogens or particles, fuse with lysosomes. Within the phagolysosome, the engulfed material is degraded by various enzymes, including proteases, resulting in the generation of peptides. These peptides are then loaded onto MHC-II molecules and presented on the cell surface to activate immune responses. Therefore, the correct answer is Phagolysosome.

The activation of CD8 T lymphocytes requires MHC class I antigen presentation, CD86 co-stimulation, and IL-12. MHC class I molecules present antigens to CD8 T cells, CD86 provides a co-stimulatory signal to enhance T cell activation, and IL-12 is a cytokine that promotes the differentiation and activation of CD8 T cells. This combination of elements is necessary for the activation of CD8 T lymphocytes.

B lymphocytes, macrophages, and dendritic cells are all antigen presenting cells involved in MHC-II-restricted antigen presentation. These cells play a crucial role in the immune response by capturing, processing, and presenting antigens to CD4 T lymphocytes. B lymphocytes present antigens to CD4 T lymphocytes through MHC-II molecules, while macrophages and dendritic cells also express MHC-II molecules and present antigens to CD4 T lymphocytes. This process is essential for the activation of CD4 T lymphocytes and the initiation of an effective immune response against pathogens.

The minimum number of different MHC-I alleles that can be present on the cell surface of a normal, healthy individual is 3. MHC-I molecules are highly polymorphic, meaning they have many different alleles. Each individual inherits two sets of MHC-I genes, one from each parent. Since each parent can contribute a maximum of three different alleles, the minimum number of different MHC-I alleles that can be present is 3.

Depending if you have a TH1, TH2 or a TH17 response., D and F could also be correct answers

B lymphocytes, macrophages, and dendritic cells are all antigen presenting cells (APCs) involved in MHC-I-restricted antigen presentation. These cells play a crucial role in the immune response by capturing, processing, and presenting antigens to CD8 T lymphocytes. B lymphocytes are responsible for producing antibodies and presenting antigens to helper T cells. Macrophages are phagocytic cells that engulf and present antigens to T cells. Dendritic cells are specialized APCs that capture and present antigens to both CD4 and CD8 T cells, initiating an immune response. CD4 and CD8 T lymphocytes are not antigen presenting cells, but rather recognize antigens presented by APCs.

Surprisingly, people with MHC-I deficiency are not abnormally affected by viral and other intracellular infections. This is because MHC-I deficiency is mainly due to mutations in TAP-1/TAP-2, and that there probably exist compensatory pathways for peptide transport.