Comprehensive Immunology and Virology: Vaccines, Microbial Interactions, and Disease Mechanisms

How do inactivated vaccines differ from live attenuated vaccines?

Inactivated vaccines use killed microbes or chemicals so they cannot replicate, making them safer for immunodeficient people.

What is the mechanism of subunit vaccines?

They use specific pieces of a virus or bacteria, such as proteins or polysaccharides, to trigger an immune response.

What is the purpose of toxoid vaccines?

They neutralize the toxic activity produced by bacteria to create an antibody response against the toxin.

How do viral vector vaccines function?

They use a modified virus to deliver genetic blueprints to cells, which then produce viral proteins to build immunity.

What is the primary difference between viral vector and mRNA vaccines?

Viral vector vaccines use a modified virus as a delivery vehicle, while mRNA vaccines use lipid nanoparticles to deliver genetic material.

Define an ecosystem.

A dynamic and interconnected community of living organisms and their non-living surroundings.

What is the difference between a fundamental niche and a realized niche?

The fundamental niche is the full range of conditions where an organism can survive, while the realized niche is the actual range occupied due to competition.

Define mutualism in the context of symbiosis.

A relationship where both species benefit and may fail to grow independently.

How does synergism differ from mutualism?

In synergism, both species benefit, but they can survive and grow independently.

What is commensalism?

A relationship where one population benefits and the other is unaffected.

What is colonization resistance?

The ability of an established indigenous community to prevent the invasion of foreign populations.

Define neutralism.

A lack of interaction between populations due to low density and low metabolic activity, allowing them to co-exist without competing.

What is a keystone species?

A species that plays a role in its community far more important than its relative abundance suggests.

What are indicator species?

Species whose presence, absence, or abundance reflects specific traits or characteristics of an ecosystem.

What are biofilms?

Assemblages of bacteria adhered to a surface and encased in an adhesive matrix that traps nutrients and prevents detachment.

What is the primary function of the innate immune system?

It provides a rapid, non-specific first line of defense using mechanisms like phagocytosis and pattern recognition receptors.

What distinguishes the adaptive immune system from the innate system?

The adaptive system is highly specific, recognizes unique antigens, and possesses immunological memory.

What are Pattern Recognition Receptors (PRRs)?

Receptors in the innate immune system that detect common microbial molecules.

What is the role of B-cells in the immune system?

They are responsible for antibody production and contribute to immunological memory.

What are phagocytes?

Cells such as neutrophils and macrophages that ingest and destroy pathogens.

What is the function of platelets in immunity?

They assist in wound repair, blood clotting, and can form NETs (neutrophil extracellular traps).

Define the immune system as a whole.

An integrated system of organs, tissues, and cells that differentiates self from non-self and neutralizes pathogens.

What is the primary function of chemokines?

To recruit immune cells to sites of infection.

What is the role of the complement system?

A series of proteins that enhance inflammation, attract phagocytes, and directly kill pathogens.

Which antibody class is the first produced during an infection?

IgM (a pentamer).

Which antibody class is associated with allergic reactions?

IgE.

What is the function of monocytes?

To engulf foreign material and differentiate into macrophages.

What is the role of Treg cells?

To regulate and reduce excessive immune responses.

How does the skin act as a physical barrier?

It is acidic, salty, and frequently sheds its top layer to remove pathogens.

What is the role of sebum in the skin?

It is produced by sebaceous glands and blocks bacteria from entering sweat glands.

What is the primary function of lysozyme in the body?

To break down bacterial cell walls.

What is the definition of an obligate intracellular parasite?

An organism or agent that cannot replicate independently and requires a host cell.

What is the difference between positive-sense and negative-sense RNA viruses?

Positive-sense RNA can be directly translated into proteins, while negative-sense RNA must first be converted into positive-sense RNA.

What is the primary cause of death in severe COVID-19 cases?

Pneumonia caused by infection of cells in the lower respiratory tract.

What is the difference between antigenic shift and antigenic drift in Influenza A?

Antigenic shift is a major change resulting in a new subtype, while antigenic drift involves small mutations in surface proteins.

What role do pigs play in the evolution of Influenza A?

They act as an intermediate host that can be infected by strains from different animals, facilitating antigenic shift.

What are the two main surface proteins of the Influenza virus?

Hemagglutinin (HA) and Neuraminidase (NA).

How can an immune response indirectly damage the body?

Excessive or prolonged immune responses can cause significant tissue damage, such as cytokine storms.

What are the common symptoms of measles?

Fever, cough, and red eyes.

What is post-polio syndrome?

A condition occurring years after the initial infection characterized by chronic muscle weakness, fatigue, and joint pain.

How is Norovirus primarily transmitted?

Through foodborne contamination or contact with infected surfaces.

What is the primary transmission route for Herpes Simplex Virus (HSV)?

Direct contact with sores or bodily fluids.

What is the cause of chickenpox?

Varicella-zoster virus (a DNA virus).

How is the Epstein-Barr virus (EBV) typically transmitted?

Primarily through saliva.

What are the typical symptoms of Epstein-Barr virus infection?

Fatigue, fever, inflamed throat, and swollen lymph nodes.

What is the function of opsonization?

To coat pathogens with antibodies, making them easier for phagocytes to identify and remove.

What is antibody-dependent cellular cytotoxicity?

A process where antibodies bind to large pathogens, signaling immune cells to destroy them.