Question

2 part problem.

The past couple of months have been hard for Doug and Stacy. Their first baby, Ryan, arrived five weeks early. Ryan stayed in the hospital for three weeks after he was born, because there were some issues with his lungs. Nevertheless, the doctors have assured Doug and Stacy that he will be fine. The first month at home has been exciting but stressful, and Doug and Stacy are just beginning to settle into their roles as new parents. For the past couple of days, baby Ryan has been irritable, and Stacy notices that he isn’t eating as much as usual. A day or so later, Ryan has a low fever and a slight cough, and he has been sneezing. Doug and Stacy notice a “raspy” sound when Ryan breathes. Worried that there might be problems related to Ryan’s earlier lung issues, they call Ryan’s pediatrician immediately.

Dr. Connors examines Ryan and collects a nasal wash (saline squirted into and immediately with- drawn from the nostril) to send for lab analysis. Noting Ryan’s labored breath sounds and his previous lung issues, Dr. Connors admits Ryan to the hospital so he can be monitored until the lab results return. The analysis of the nasal wash reveals that Ryan has respiratory syncytial virus (RSV). Doug and Stacy are scared by the diagnosis— Ryan’s been through so much already. Dr. Connors tells them that premature babies like Ryan are at risk for acquiring RSV infection; it is actually very common. The Centers for Disease Control and Pre- vention (CDC) estimates that almost all children become infected with RSV before their second birthday. There is no specific treatment for RSV, but because of Ryan’s medical history, Dr. Connors keeps Ryan in the hospital. Over the next couple of days, Ryan develops bronchiolitis (inflammation of the bronchi- oles). He is treated with supplemental oxygen and suctioning of mucus to help him breathe more easily. During the next 10 days, Ryan’s condition progressively improves, and he returns home, fully recovered.

1. The laboratory test used to identify RSV in Ryan's nasal wash is based on detecting RSV antigen in the sample. Describe one approach to identifying antigens in a sample from a patient.

2. Even though RSV infection in infants is common, a vaccine does not currently exist. Imagine you are designing a recombinant vaccine for RSV--what viral components would you use in your vaccine? Justify your choice.

Answer 1

RSV is caused by a group of paramyxoviruses and belong to the group of pneumoviruses. It has two prevalent strains RSV-A and RSV-B.

To test RSV antigen in the sample we can use immunofluorescence test (IFT). IFT is a method used to identify pathogen specific antigen or antibody in sample collected from patient using fluorescence. A fluorochrome protein molecule is used to do this. Depending upon the material used and dye fluorochrome releases energy which results in fluorescence.

In this method sample collected from patient is applied on the plate and antibodies specific to the antigen are added into the plates with antigen. The antibodies used are labeled with fluorochrome to give fluorescence.

2. As viruses genetic material is prone to errors it is difficult to create a vaccine against viruses. RSV has RNA as genome and it has highly conserved lipoprotein which functions as antigen. This lipoprotein sequence is highly conserved in all the strains of the viruses. I would prefer to use this lipoprotein present in the membrane of virus for vaccine research.