Immunity and Infection Quiz

Immunity and Infection

• Recovery from chickenpox involves the administration of antibodies from an immune individual.
• Acquired immunity is a type of immunity that occurs after exposure to a pathogen or antigen.
• Memory B cells and T cells are responsible for acquired immunity.
• MHC I class molecules are responsible for presenting antigens to CD8+ T cells.

Innate Immune Response

• Dendritic cells, macrophages, and B lymphocytes are involved in the innate immune response.
• The innate immune response is non-specific and rapid.
• TLR4 is a receptor involved in the recognition of pathogens.
• IL-12 is a cytokine that initiates pro-inflammatory responses.
• Selectins are involved in the recruitment of immune cells to the site of infection.
• The phagocytic activity of neutrophils contributes to microbial destruction within phagosomes.

Complement System

• IgG and C3b are molecules that function as opsonins.
• The alternative, classical, and lectin pathways are the three pathways of complement activation.
• Newborns receive antibodies from their mothers through IgG across the placenta and IgA via breast milk.

Defense against Pathogens

• IgE antibodies and eosinophils play a significant role in the defense against helminths.
• Plasmacytoid dendritic cells play an important role in the selection of B cells with high-affinity receptors.
• Macrophages and complement are involved in the defense against bacterial infections.
• Lipopolysaccharide (LPS) is a characteristic of Gram-negative bacteria.

Transplantation

• Indirect allorecognition occurs when T cells recognize processed peptide of allogeneic MHC molecule bound to self MHC molecule on host APC.
• Hyperacute graft rejection is mediated by preexisting antibodies in the host circulation that bind to donor endothelial antigens.

Bacterial Infections

• Streptokinase secreted by S. pyogenes converts plasminogen to plasmin.
• The mucoid or smooth capsule in pneumococcus promotes bacterial colonization.
• S. aureus is distinguished from other staphylococci by the production of free coagulase.
• Enterococcus faecalis inhibits Streptococcus mutans in the oral cavity.

Fungal Infections

• Neutrophils and macrophages play the most important role in defending against Aspergillus infections.
• Malassezia furfur is a common cause of seborrheic dermatitis.
• Tinea corporis is characterized by clearly circumscribed, pruritic, desquamated areas of skin.
• Amphotericin B is known for its nephrotoxicity.

Viral Infections

• Single-stranded positive RNA viral genomes can be directly translated by the host cell's ribosomes.
• Hemagglutinin (HA) in influenza viruses binds to sialic acid.
• Herpes viruses are known for their ability to establish latent infections in the host cell.
• Antigenic shift refers to a major genetic rearrangement creating new viral subtypes which can cause pandemics.
• SARS-CoV-2 is the coronavirus responsible for the COVID-19 pandemic.
• Acyclovir is an antiviral drug that inhibits viral DNA synthesis by inhibiting viral DNA polymerase.
• Coxsackie A virus can cause hand, foot, and mouth disease.
• Rubella virus can cause severe congenital infections.