Question

You are a T-helper cell in your immune system and are deciding what parts of the immune system to marshall against an incoming invader. For this assignment, you will be presented with a pathogen and its arsenal of virulence factors that it can use against you. Your job, if you choose to accept it, is to pick the portions of the immune system that you will use against each virulence factor and then describe how that immune system part inactivates the target virulence factor.
Here are your potential adversaries, write about Rhinovirus.

Virulence factor/antigen	Made from	Effect on the host
Capsid proteins	Protein	These bind to and recognize the host by binding to Inter-Cellular Adhesion Molecule 1 or to Cadherin-related family member 3 protein, depending upon the viral species (A, B, or C). These receptors are found on cells of the respiratory epithelium.
RNA polymerase	Protein	The enzyme that replicates the DNA.

In your short answer, I want you to answer the following questions. You can do this explicitly or implicitly:

Name one part of innate immunity that could prevent infection by your chosen pathogen.

What parts of the immune system are involved in recognizing each virulence factor/antigen? You may use the same immune system part to counteract several different virulence factors/antigens

What is more important for stopping this infection, humoral (antibodies) or cell-mediated immunity? Why do you think so?

What cells are involved in taking care of the bacteria or infected cell and how do they do it?

No more than 400 words.

Answer 1

1)Mucosal lining of respiratory tract acts as a barrier for foreign pathogens. It can prevent infection by rhinovirus. But it is not very potent . Macrophages are potent enough. They identify virus and release cytokines thus attracting other cells like neutrophils.

2)Capsid proteins- they bind to receptors on epithelial cells of respiratory tract which induces secretion of cytokines and chemokines like IL-1, IL-6,IL-8, GM-CSF etc. This attracts neutrophils, macrophages and eosinophils.

3) humoral immunity

Antibodies neutralise viruses and are most effective when virus is present on moist surfaces or serum whereas T cell destroy infected cells

4)cells involved are macrophages, neutrophils, eosinophils, t lymphocytes and b lymphocytes.

When bacteria enters human body and binds to a cell macrophages identify bacteria and are able to differentiate it from body cells due to specific proteins present on surface of each cell. They then secrete cytokines which attracts other cells like neutrophils, eosinophils, and lymphocytes.

Neutrophils are killer cells which get attached to bacterial cell and make holes in it. Bacteria absorbs water and swells up. Thus it causes lysis of cells. cytotoxic T- lymphocytes cause lysis . B- lymphocytes secrete antibodies in response to infection which neutralises toxins produced.