Immunology Overview

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Questions and Answers

What is the initial step in the lytic cycle of virus replication?

Attachment to the bacterial cell (correct)

Replication of phage DNA

Transcription of viral DNA

Assembly of viral DNA and proteins

In which step does the host's enzymes begin transcribing the viral DNA into mRNA?

Replication

Transcription (correct)

Attachment

Penetration

Which of the following is an example of natural active immunity?

Injection of hepatitis B immune globulin

Transplacental transfer of antibodies

Vaccination against measles

Natural infection with chicken pox (correct)

What occurs during step 4 of the lytic cycle?

Synthesis of protein and replication of phage DNA Signup and view all the answers

Which form of passive immunity is gained through maternal transfer?

Colostrum transfer Signup and view all the answers

What is the role of lymphokines in HIV replication?

They secrete chemical compounds onto the antigen membrane Signup and view all the answers

What characterizes artificial passive immunity?

Injection of serum containing antibodies from another individual Signup and view all the answers

During which step of the lytic cycle does the viral DNA get injected into the host?

Penetration Signup and view all the answers

What is the primary role of macrophages in the immune response?

They identify pathogens by ingesting them. Signup and view all the answers

Which type of cells primarily mediate the inflammatory response?

Macrophages Signup and view all the answers

What is the function of Langerhans cells?

To act as antigen presenting cells that communicate between immune systems. Signup and view all the answers

What feature distinguishes Natural Killer cells from other white blood cells?

They destroy infected and diseased cells, especially cancer cells. Signup and view all the answers

What outcome is indicated by painful lymph nodes during palpation?

An infectious process. Signup and view all the answers

Which of the following roles do dendritic cells play in the immune system?

They act as messengers between the innate and adaptive immune systems. Signup and view all the answers

Cytokines are primarily involved in which aspect of the immune response?

Modulating immune response. Signup and view all the answers

Which immune response is primarily stimulated by antigens presented on macrophage surfaces?

Cell-Mediated Immunity (CMI) Signup and view all the answers

What is the recommended action if a tissue is not available when coughing or sneezing?

Cough or sneeze into your upper sleeve. Signup and view all the answers

What is the primary purpose of the annual flu vaccine for people aged 6 months and older?

To create a new immune response against evolving viruses. Signup and view all the answers

Why can influenza viruses evade the immune system over time?

They develop new mutations and variants. Signup and view all the answers

What should be avoided in close contact, especially for individuals with chronic diseases?

Pigs or camels. Signup and view all the answers

Which setting is crucial for vaccine administration?

A place where allergic reactions can be treated. Signup and view all the answers

What are the two mechanisms called that allow influenza viruses to create new variants?

Antigenic drift and shift. Signup and view all the answers

What limitation do patients with autoimmune diseases face concerning the flu vaccine?

They cannot be given live vaccines. Signup and view all the answers

What key hygiene practice should be maintained to help prevent the spread of infections on a farm?

Frequent hand washing with soap and water. Signup and view all the answers

What is a key characteristic of HIV as a virus?

It is a retrovirus. Signup and view all the answers

Which demographic currently shows the highest infection rates for HIV?

Pre-adolescents to adolescents (aged 13 to 34). Signup and view all the answers

What is one method through which HIV is transmitted?

Pregnancy and breastfeeding. Signup and view all the answers

How does HIV integrate into the host's cells?

By becoming part of the cell's DNA. Signup and view all the answers

Which of the following fluid types is NOT a known route of HIV transmission?

Saliva. Signup and view all the answers

What annual statistic is reported regarding new HIV infections in the United States?

36,400 new infections. Signup and view all the answers

What is the process called where newly formed viral particles bud off from the host cell?

Assembly and Release. Signup and view all the answers

Which of the following is a common misconception about HIV transmission?

It can be contracted through sharing utensils. Signup and view all the answers

What is the purpose of the HIV-1 differentiation assay?

To differentiate between HIV-1 and HIV-2 Signup and view all the answers

What is the significance of the window period in HIV testing?

No viral load can be detected during this period Signup and view all the answers

What does the acronym PrEP stand for in HIV prevention?

Pre-exposure prophylaxis Signup and view all the answers

What is a major limitation of PrEP?

It is ineffective if not used consistently Signup and view all the answers

What can result from cross-infection with another HIV-seropositive person?

Increased severity of the HIV infection Signup and view all the answers

Which of the following is NOT a form of behavioral intervention for HIV prevention?

Antiretroviral therapy Signup and view all the answers

What does the phrase 'U=U' imply in the context of HIV?

Undetectable equals untransmittable Signup and view all the answers

Which of the following tests is used to directly detect the presence of the HIV virus?

HIV-1 p24 antigen test Signup and view all the answers

Study Notes

Macrophages

Ingest and digest pathogens.
Present antigens on their surface to activate lymphocytes.
Release cytokines, stimulating cytokine secretion.
Modulate immune response and participate in tissue repair.
Mediate immediate inflammatory response and stimulate long-lasting immune responses (AMI and CMI).

Dendritic Cells

Have dendrites found in neurons.
Act as messengers between innate and adaptive immune systems.
Are antigen-presenting cells.

Natural Killer (NK) Cells

Destroy infected and diseased cells, particularly cancer cells.

Delayed Hypersensitivity

Occurs when T-lymphocyte activity happens without a humoral response.

Acquired Specific Immunity: Active

Natural: Contact with antigen through infection (e.g., chickenpox, measles, mumps).
Artificial: Immunization with antigen (e.g., vaccines).

Acquired Specific Immunity: Passive

Natural: Transplacental and colostrum transfer from mother to child (e.g., maternal immunoglobulins).
Artificial: Injection of serum with antibodies (e.g., hepatitis B immune globulin).

Preventing MERS-CoV Infection

Regular handwashing.
Good personal hygiene.
Avoiding close contact with infected individuals and camels.

Influenza Virus: Antigenic Drift & Shift

Mechanisms that cause changes in surface proteins, helping the virus evade the immune system.
Antigenic drift: small, gradual changes due to mutations.
Antigenic shift: creates new variants.

Influenza Vaccine

Recommended for all people 6 months and older annually.
Administered intranasally or via injection.
Live vaccines should be avoided by immunocompromised individuals.

HIV/AIDS

Retrovirus originating from chimpanzees.
First cases reported in the US in 1981.
36,400 new infections annually, with MSM being the largest affected group.
Transmitted through infected blood, semen, vaginal secretions, breast milk; during pregnancy, breastfeeding, organ transplant, unprotected sex.
Not spread via tears, saliva, urine, emesis, sputum, feces, sweat, respiratory droplets, or enteric routes.

HIV Testing

Window period: 10-90 days depending on the test type (NAT, antigen/antibody, rapid antigen/antibody, antibody tests).

HIV Prevention

Health education, behavioral interventions (condoms, PrEP, abstinence, monogamy, dental dams).
HIV testing, PrEP (tenofovir disoproxil fumarate/emtricitabine), U=U (Undetectable=Untransmittable).
Safe sex practices, avoiding unprotected sex with HIV-positive individuals.
Healthcare provider precautions: hand hygiene, PPEs.

HIV Drug Therapy

Information not provided in the text.

Lytic Cycle: Virus Replication

Attachment: virus attaches to the bacterial cell surface.
Penetration: viral DNA/RNA injected into the bacterial cell.
Transcription: host enzymes transcribe viral DNA into mRNA.
Replication and protein synthesis: viral DNA replicated, viral proteins synthesized.
Assembly: viral DNA and proteins assemble into new viruses.
Release: new viruses bud off from the host cell.

Studying That Suits You

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Description

Test your knowledge on various immune cells and their functions, including macrophages, dendritic cells, and natural killer cells. Explore the concepts of acquired specific immunity and delayed hypersensitivity in this comprehensive quiz. Perfect for students studying immunology or related fields!