(4.4) SECONDARY IMMUNODEFICIENCIES

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Questions and Answers

What role do bacterial immunoglobulin A binding proteins play in infection?

They directly impair the function of IgA. (correct)

They enhance the production of IgA.

They neutralize antibodies produced by the host.

They increase the strength of mucosal membranes.

How does the protein SLLP7 contribute to immune evasion?

By directly destroying T cells.

By triggering an allergic response in the host.

By enhancing phagocytosis of pathogens.

By mimicking host cells to avoid detection. (correct)

What is a superantigen?

A factor that reduces the effectiveness of vaccines.

A type of antibody produced by the host.

A molecule that selectively kills T cells.

A molecule that stimulates polyclonal T cell activity non-specifically. (correct)

What can excessive activation of T cells due to superantigens lead to?

Autoimmune disorders. Signup and view all the answers

Which mechanism allows bacteria to effectively subvert the normal immune response?

Hiding from the immune system by mimicking host molecules. Signup and view all the answers

What is the purpose of quarantining individuals infected with HIVN1?

To control and limit the spread of the virus Signup and view all the answers

How do African trypanosomes evade the host's immune response?

By changing their surface antigens through gene conversion Signup and view all the answers

What happens when the body produces antibodies against the first surface antigen of African trypanosomes?

The trypanosome expresses a different surface antigen Signup and view all the answers

Which disease is caused by African trypanosomes?

African sleeping sickness Signup and view all the answers

What is a significant risk associated with HIVN1 transmission from animals to humans?

Vulnerability of the entire human population to infection Signup and view all the answers

What mechanism allows the trypanosome to continuously infect the host despite the immune response?

Changing expression of variable surface antigens Signup and view all the answers

What role does frequent animal testing play in managing HIVN1 outbreaks?

To ensure no new viruses are introduced Signup and view all the answers

In the context of chronic viral infections like HIV, what typically happens during an antigenic shift?

The virus changes its protein structures to evade immune detection Signup and view all the answers

What is the significance of having many inactive genes in African trypanosomes?

They provide a variety of surface antigens for immune evasion Signup and view all the answers

What is a primary defense strategy against the spread of novel viruses like HIVN1?

Isolation and quarantine Signup and view all the answers

What is the initial interaction that allows HIV to enter a host cell?

gp120 binding to CD4 Signup and view all the answers

Which statement accurately describes the viral life cycle after HIV enters a T cell?

The viral DNA integrates into the host genome as a provirus Signup and view all the answers

How does the presence of the provirus impact T cell function over time?

It leads to persistent low-level transcription of HIV proteins. Signup and view all the answers

Which of the following describes the consequence of falling CD4 T-cell counts?

Increased frequency of opportunistic infections Signup and view all the answers

What is the role of Tat and Rev proteins in HIV-infected cells?

They alter the pattern of provirus transcription. Signup and view all the answers

Which of the following is NOT a potential causative environmental factor for secondary immune deficiencies?

Genetic mutations Signup and view all the answers

What is a common characteristic of individuals with secondary immune deficiencies?

Inability to eliminate infectious agents effectively Signup and view all the answers

HIV primarily targets which type of immune cell?

CD4 T cells Signup and view all the answers

Which protein is essential for HIV to convert its RNA into DNA?

Reverse transcriptase Signup and view all the answers

What are the primary components encoded by the gag, pol, and env genes in HIV?

Structural proteins of the virion Signup and view all the answers

What distinguishes HIV-1 from HIV-2 at the genetic level?

Vpu and Vpx genes Signup and view all the answers

Which of the following statements is true regarding the life cycle of HIV?

HIV integrates its DNA into the host's genome Signup and view all the answers

What is a significant physiological effect of malnutrition on the immune system?

Reduced function of immune cells Signup and view all the answers

Which of the following best describes the long-term impact of therapeutic treatments such as chemotherapy on the immune system?

Possible induction of secondary immune deficiencies Signup and view all the answers

A genetic deficiency in the CCR5 co-receptor offers what kind of advantage against HIV?

Confers resistance to infection Signup and view all the answers

Study Notes

Pneumonia Causes

Strep pneumoniae causes pneumonia
Strep-iogenes causes strep throat
Several serotypes of S. pneumoniae exist, each with different antigens (e.g., triangles, rectangles, orange, green, blue)
Infection with one serotype doesn't guarantee immunity to others
Immune response to infection is needed for each serotype

Antigenic Drift and Shift

Antigenic drift: Minor mutations in viral surface antigens, a gradual change.
Antigenic shift: Major jump in viral surface antigens due to reassortment of genes from different strains.
Influenza viruses have segmented genomes that allow for the reassortment of genes.
Point mutations lead to antigenic drift
Shifts or jumps allow new strains or subtypes to emerge.
- This typically involves a mix of strains from an animal host to humans (e.g., H5N1 in humans)

Influenza Viruses

Antigenic differences between influenza strains lead to the need for annual vaccines
Surface antigens on the virus create antibodies to fight the virus
Antibodies to one strain may not be effective against another strain
Influenza uses gene conversions or antigenic variation to evade immune responses (in the case of trypanosomes).
Viral surface antigens change over time causing the immune system to need to create more antibodies.

Herpes Virus

Herpes viruses are known to persist in the host
They can go latent with the immune system and hide to avoid detection, reactivation can occur under stress
Herpes viruses have surface antigens that cause immune response
Reactivation can cause reinfection and symptoms

Superantigens

Superantigens can trigger T cells to divide and cause autoimmune disorders.
Superantigens interact non-specifically with major histocompatibility complex class II molecules and T cell receptors.
They disrupt the normal immune response
Examples include Streptococcus pyogenes and Staphylococcus aureus superantigens.

Immunodeficiency Disorders

Immunodeficiency disorders are conditions where parts of the immune system fail to function efficiently
This can be due to genetic factors (primary) or environmental factors (secondary)
HIV is an example of a viral infection that causes immunodeficiency
Cancer treatments and malnutrition can also lead to secondary immunodeficiency.

HIV

HIV (Human Immunodeficiency Virus) attacks T cells (and other parts of the immune system).
This weakens the immune system, increasing susceptibility to infections and diseases.
Infection rates have been tracked from 2018 to the present.
Significant numbers of people contract HIV, as well as deaths per year.

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Description

This quiz focuses on the causes of pneumonia, specifically related to Streptococcus pneumoniae and the mechanism of antigenic drift and shift in influenza viruses. It covers the various serotypes of pathogens, their immune responses, and the implications for vaccine development. Test your knowledge on these important concepts in respiratory infections.