Question 1

Which of the following is the most common secretory immunoglobulin&#10;A) IgM&#10;B) IgG&#10;C) IgE&#10;D) I&#947;&#948;&#10;E) IgA

Accepted Answer

IgA is the most common secretory immunoglobulin, as it is found in high concentrations in secretions such as saliva, tears, breast milk, and mucus. It plays a role in protecting mucosal surfaces from infection by binding to pathogens and preventing them from entering the body.

Question 2

Which of the following statements about the fragment crystallisable (Fc) portion of the Ig molecule is TRUE?&#10;A) The Fc portion where the Ig binds to antigen&#10;B) There are two Fc portions&#10;C) The Fc portion is where the Ig binds to receptors present on effector molecules and cells&#10;D) The Fc portion helps the Ig act as an opsonin&#10;E) The Fc portion binds the Ig to a secretory component

Accepted Answer

The Fc portion of the Ig molecule is not where the Ig binds to antigen (A), nor are there two Fc portions (B). The Fc portion is where the Ig binds to receptors present on effector molecules and cells, such as the Fc receptors on phagocytes (C). The Fc portion also helps the Ig act as an opsonin (D), but it is not where the Ig binds to a secretory component (E).

Question 3

Selective deficiency of IgA is associated with a...&#10;A) Reduced vaccine response&#10;B) Improved vaccine response&#10;C) Lower incidence of infections&#10;D) Higher incidence of infections&#10;E) Impaired DTH response

Accepted Answer

Selective deficiency of IgA is associated with a higher incidence of infections, particularly involving the respiratory and gastrointestinal tracts. This is because IgA is a crucial antibody for mucosal immunity and helps neutralize pathogens at mucosal surfaces. The reduced ability to produce this antibody leaves individuals more susceptible to infections in these areas.

Question 4

What is the main function of secretory component?&#10;A) To join two IgA monomers as dimeric IgA&#10;B) To allow IgA translocation across the mucosal epithelium&#10;C) To protect secretory IgA against degradation by proteases&#10;D) To allow antigen binding to the Fab portions of secretory IgA&#10;E) To increase the rate at which IgA is secreted by plasma cells

Accepted Answer

The main function of secretory component is to protect secretory IgA against degradation by proteases. Without secretory component, IgA would be easily degraded by proteases in the mucosal environment. Secretory component also helps to anchor secretory IgA to mucus, allowing it to remain in the mucosal environment for a longer period of time.

Question 5

Which of the following methods of reporting salivary SIgA is thought to best reflect the amount of IgA available to the mucosal surfaces?&#10;A) SIgA concentration&#10;B) SIgA relative to saliva osmolality&#10;C) SIgA relative to total saliva protein concentration&#10;D) SIgA secretion rate&#10;E) SIgA relative to plasma albumin concentration

Accepted Answer

SIgA secretion rate is thought to best reflect the amount of IgA available to the mucosal surfaces because it takes into account both the concentration of SIgA in the saliva and the rate of saliva production. This method provides a more accurate assessment of the amount of IgA being secreted at the mucosal surfaces compared to the other options listed.

Question 6

Which of the following statements is FALSE regarding the study of Gleeson et al. (1999b) in a cohort of elite Australian swimmers?&#10;A) SIgA concentration increased with each additional month of training&#10;B) SIgA concentration fell with each additional month of training&#10;C) Pre-season SIgA concentration was predictive of infection frequency&#10;D) Mean pre-training SIgA concentration was predictive of infection frequency&#10;E) None of the above

Accepted Answer

The study by Gleeson et al. (1999b) found that SIgA concentration fell with each additional month of training, not increased.

Question 7

Neville et al. (2008) found that a fall to less than 40% of an individual's usual healthy SIgA concentration was indicative of...&#10;A) A 25% chance of contracting an infection within 3 weeks&#10;B) A 50% chance of contracting an infection within 3 weeks&#10;C) A 75% chance of contracting an infection within 3 weeks&#10;D) A 100% chance of contracting an infection within 3 weeks&#10;E) A decrease in infection risk over the next 3 weeks

Accepted Answer

The answer of Neville et al. (2008) found that a...

Question 8

Salivary lactoferrin concentrations are reported to be...&#10;A) Lower in elite athletes compared with sedentary controls&#10;B) Related to saliva IgA concentration&#10;C) Lower in response to a graded exercise to exhaustion&#10;D) An indicator of subjective fatigue&#10;E) All of the above

Accepted Answer

The answer of Salivary lactoferrin concentrations are reported to be...&#10;A)...

Question 9

The changes in salivary SIgA with strenuous acute exercise may reflect altered mobilisation of the pIgR as a consequence of increased sympathetic nervous system activation.

Accepted Answer

Strenuous acute exercise can increase sympathetic nervous system activation, which can alter the mobilization of pIgR, ultimately affecting salivary SIgA levels. Therefore, the statement is true.

Question 10

Decreases in salivary flow rate during high intensity exercise are most likely to be caused by increases in plasma cortisol.

Accepted Answer

Decreases in salivary flow rate during high intensity exercise are primarily due to sympathetic nervous system activation, which diverts blood away from the salivary glands, not directly due to increases in plasma cortisol.

Deck 6: Effects of Exercise on Mucosal Immunity