The initial antigen exposure elicits an extrafollicular response (1) that results in the rapid appearance of low IgG antibodies titres. As B cells proliferate in germinal centers and differentiate into plasma cells, IgG antibody titres increase up to a peak value (2), usually reached 4 weeks after immunization. The short life span of these plasma cells results in a rapid decline of antibody titres (3), which eventually return to baseline levels (4). In second immune responses, booster exposure to antigen reactivates immune memory and results in a rapid (<7 days) increases (5) of IgG antibody titre. Short-lived plasma cells maintain peak antibody levels (6) during a few weeks --- after which serum antibody titres decline initially with the same rapid kinetics as following primary immunization (7). Long-lived plasma cells that have reached survival niches in the bone marrow continue to produce antigen-specific antibodies, which then decline with slower kinetics (8). Note: This generic pattern may not apply to live vaccines triggering long-term IgG antibodies for extended periods.
MMR is an attenuated (weakened) live virus vaccine.
MacLennan (2003) stated that, "In adaptive antibody responses, B cells are induced to grow either in follicles where they form germinal centers or in extrafollicular foci as plasmablasts (a precursor of a plasma cell)."
"The most abundant class of immunoglobulins in the blood is IgG (73%)...IgG is present in plasma and external secretions and is expressed on the B-cell membrane. (Schwartz, 2018)
Plasma cells are not really a distinct cell line but differentiate from a particular set of lymphocytes (the B lymphocytes) during immune response...The major function of plasma cells is to synthesize and secrete antibodies. (Widmaier, 2008)
1. Cup the respirator in your hand, with the nosepiece at your fingertips, allowing the handbands to hang freely below your hand.
2. Position the respirator under your chin with the nosepiece up. Pull the top strap over your head resting it high at the top back of your head. Pull the bottom strap over your head and position it around the neck below the ears.
3. Place your fingertips from both hands at the top of the metal nosepiece. Using two hands, mold the nose area to the shape of your nose by pushing inward while moving your fingertips down both sides of the nosepiece. Pinching the nosepiece using one hand may result in improper fit and less effective respirator performance. Use two hands.
4. Perform a User Seal Check prior to each wearing. To check the respirator-to-face seal, place both hands completely over the respirator and exhale. Be careful not to disturb the position of the respirator. If air leaks around nose, readjust the nosepiece as described in step 3. If air leaks at the respirator edges, work the straps back along the sides of your head. If you cannot achieve proper seal, do not enter the isolation or treatment area. See your supervisor.
Removal Instructions
See step 2 of Fitting Instructions and cup respirator in hand to maintain position on face. Pull bottom strap over head. Still holding respirator in position, pull top strap over head and remove respirator.
Fit Test
MacLennan, I.C., & Toellner, K. M. (2003) Extrafollicular antibody responses. Immunological Reviews, 194:8-18. Retrieve from https://www.ncbi.nlm.nih.gov/pubmed/12846803/
Widmaier, E.P., & Raff, H. (2008). Vander’s Human Physiology: The Mechanisms of Body Function. New York, NY: McGraw-Hill.
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