Immunology Basics

Immunology

• Humoral immunity: related to B-cells and antibody production

• Cellular immunity: related to T-cells and cell-mediated immune responses

• Primary lymphotic organism: bone marrow (where B-cells mature)

• Secondary lymphotic organism: spleen, lymph nodes, and other tissues (where T-cells mature)

• Mast cells: involved in allergic reactions and immune responses

• Killer cells: Natural Killer cells (NK cells) and Cytotoxic T cells

• Immunoglobulin: also known as antibodies, produced by B-cells

• Natural Killer: type of immune cell that can kill infected cells or tumor cells

• Immune Complex: formed when antibodies bind to antigens

• TNF: Tumor Necrosis Factor, a cytokine involved in immune responses

• Cytokines: signaling molecules involved in immune responses

Protein A and Staphylococcus aureus

• Protein A: a bacterial surface protein that binds to the Fc portion of IgG1

Microbiology

• Aminoglycosides antibiotics: have an extended spectrum and include antibiotics such as streptomycin
• Phenylanine deamination test: used to detect the presence of bacteria
• Disc diffusion test: used to determine antibacterial susceptibility
• Beta hemolysis: a type of hemolysis caused by streptococcal group, characterized by complete hemolysis and a positive result for Bacitracin test
• Polymyxin B: a type of polymyxin antibiotic used to treat infections

Antibiotics

• Penicillins: inhibit cross-linkage of peptidoglycans in bacterial cell walls, most do not cross the blood-brain barrier, and dosage adjustment is not required in renal failure
• Norfloxacillin: inhibits nucleic acid synthesis
• Chloramphenicol: inhibits protein synthesis
• Trimethoprim: inhibits nucleic acid synthesis
• Rifampicin: inhibits nucleic acid synthesis
• Sulfasalazin: inhibits nucleic acid synthesis
• Ciprofloxacin: inhibits DNA synthesis
• Cefoxitin: inhibits cell wall synthesis
• Tobramycin: inhibits protein synthesis
• Metronidazole: used to treat giardiasis, causes a metallic taste in the mouth, and inhibits alcohol dehydrogenase

Flow of Genetic Information

• The correct sequence of genetic information flow is: DNA to RNA to protein

DNA Synthesis

• The correct DNA sequence synthesized using 5'-CAGTTCGGA-3' as a template is: 3'-GTCAAGCCT-5'

tRNA Binding Site

• During elongation in translation, the incoming charged tRNA molecule binds to the A site of the ribosome

Bacterial Transcription

• The σ subunit of the RNA polymerase is involved in the initiation stage of bacterial transcription

Transcriptional Control

• Negative transcriptional control: inhibits gene expression by blocking transcription
• Positive transcriptional control: enhances gene expression by stimulating transcription
• Both negative and positive transcriptional control can be used to regulate both inducible and repressible genes

True or False

• True: Innate immunity is antigen-independent and the first defense
• False: Thymus is the site for maturation of T cells and B cells (only T cells)
• False: Peyer patch is a mini lymph node (it is a type of lymphoid tissue)
• False: Macrophage is the only source of interleukin-6 (IL-6) (other cells can also produce IL-6)
• False: Ig M antibodies play a role in protection against helminth infection (IgE antibodies are involved in protection against helminth infection)

Immune System

• The immune response is initiated at the site of lymph nodes
• Interferon-y (IFN-y) is produced by natural killer cells and T cells
• Macrophages produce oxygen-dependent compounds, including nitric oxide
• Ig M is the first immunoglobulin produced after antigen exposure, such as bacteria
• An antigen is a substance capable of eliciting a specific immune response