In: Biology
At birth, Baby Joe appeared to be a normal, healthy baby boy. Both of his parents were in their late twenties and were healthy as well. At four weeks of age, Joe developed a middle-ear infection (called otitis media). He suffered from recurrent ear infections over the next three months, which required antibiotic treatment. Joe’s pediatrician recommended placing tubes in Joe’s ears to provide drainage of the fluid resulting from the infections. Cultures of the drainage fluid showed the presence of Haemophilus influenza, a pathogen commonly found in ear infections in infants. Starting at three months of age, Joe had four bouts of diarrhea which persisted for 3-5 days each time. Joe also was not gaining weight as rapidly as was expected during this time. This reduced weight gain and growth is referred to as “failure to thrive.” When Joe was four months old, he developed another ear infection, this one more severe than the previous infections. Joe’s parents took him to see his pediatrician, Dr. Smith. During the visit, Joe’s mother mentioned that when changing the baby’s diapers she had noticed an unusual, unpleasant odor to his urine. Dr. Smith ordered a culture of the fluid draining from Joe’s ears. Th is time, the ear drainage fluid cultures revealed the presence of Pseudomonas aeroginosa, a bacterium which is not typically present in infant ear infections. In addition, Dr. Smith determined that Joe was also suffering from a bladder infection, which caused an unpleasant odor in his urine. Questions Given the information presented above, what do you suspect is the underlying cause or causes of Joe’s health problems? Do you think the cause is genetic, environmental, or both? How might these health problems cause Joe’s slow weight gain (also called “failure to thrive”)?
Questions
1. Which types of cells are the most affected in Joe’s case? Based on this information, determine which branch of the immune system (innate or acquired) is most compromised?
2. Do you think that Joe has normal levels of antibodies present in his blood? Would they be increased or decreased? Why?
3. Use the concepts listed below to re-create the order of B cells activation and their actions when they encounter the bacterium p.aeroginosa.
•B cells become activated and proliferate (i.e. make more copies of B cells specific to p.aeroginosa).
•Activated helper T cells interact with the B cells.
•Antibodies bind to p. aeruginosa and facilitate phagocytosis via opsonisation.
•Plasma cells secrete antibodies specific to p. aeruginosa.
•Plasma cells die via apoptosis; memory cells survive in lymph nodes.
•B cells present an antigen determinant from p. aeruginosa on an MHC II molecule.
•B cells differentiate into plasma cells or into memory cel
-Due to recurrent infection, low immunity might be the suspected underlying cause of Joe's health problem. Since, the parents are healthy and quite young, the greater possibilty of infection is due to the environment factor rather than genetic cause. However, probably there can be the chance for genetic mutations but environmental factors also play a major role in Joe's disease condition. Second, Joe is not gaining weight even at 4 months of age. This type of decreased weight gain and growth is known as failure to thrive. As he has diarrhoea and other infection and most of the energy utilize by body in fighting against the infection resulting in weight loss.
1. B-cells that are required to produced antibodies are the most affected in Joe’s case. The branch of immune system involve is humoral immunity involving B-cells that is a part of Adaptive immune response.
2.Joe doesnot have normal levels of antibodies present in his blood. Upon encountering the pathogen as antigen, naive B-cells get activated and start secreting antibodies to fight against the microorganism. Therefore, rising level of antibodies has been observed.
3.The order of B cells activation and their actions when they encounter the bacterium p.aeroginosa will be as follows-
•Activated helper T cells interact with the B cells.
•B cells present an antigen determinant from p. aeruginosa on an MHC II molecule.
•B cells become activated and proliferate (i.e. making copies of B cells against p.aeroginosa).
•B cells differentiate into plasma cells or into memory cell.
•Plasma cells secrete antibodies specific to p. aeruginosa.
•Antibodies bind to p. aeruginosa and facilitate phagocytosis via opsonisation.
•Plasma cells die via apoptosis and in lymph node memory cells survive.