Immunity: Active-Passive Immunity

Passive Natural

The distinction between active and passive immunity lies in memoryThe ability to store and recall information. creation. Active immunity, whether naturally or artificially acquired, generates memory cellsThe basic structural and functional units of life.. This equips the body to fight the pathogen more effectively upon subsequent exposure. Passive immunity, while beneficial in the short term, does not lead to memory cell formation, making it a temporary solutionA homogeneous mixture of two or more substances..

When Mom give IgDs to baby across the placentaThe organ that facilitates nutrient and waste exchange between the mother and fetus., this is passive natural immunity.  It is passive because the baby wasn’t exposed to any type of antigen or epitope. It is natural because these immunoglobulins(Ig) Antibodies: Proteins produced by the immune system to target specific antigens. were given from another organismA living individual made up of cells..

Passive Acquired

Passive acquired immunity is best explained with an example: a tetanusIn this context, sustained muscle contractions due to calcium or electrolyte imbalances. shot.  A tetanus shot (by the way, when was the last time you got one?) is full of immunoglobulins for things your immune system hasn’t met yet. Since you get the immunoglobulins, this is passive immunity.  This is also acquired immunity because you were given the immunoglobulins, you didn’t make them.  No matter what, these immunoglobulins will degrade over time leaving you un-immune to those things the tetanus shot guards against.  This is why you must receive tetanus shots multiple times over your lifetime.

Passive immunity can also occur during organ transplants. Immunoglobulins from the donor can provide temporary immunity. However, they degrade over time. This happens unless B cells or stem cells are transferred along with the organ. In cases where stem cells are transferred, they can continue producing B cells, leading to prolonged immunity.  In a case study involving a peanut allergy, questions arise about how the allergy was transferred via a liverA large organ that produces bile, detoxifies blood, and stores nutrients. transplant. Did the recipient receive immunoglobulins, B cells, or stem cells from the donor?

Active Natural

Your body develops active immunity when it first responds to a pathogen. This can happen the first time you get chickenpox. The key here is that you encountered the antigen. You went through the steps of cytotoxic and humoral immunity. This process created activated B and T cells to attack.  In that process, you also made memory T and memory B cells that are long-lived.  Parents sometimes force this immunity by having chicken pox parties.  The concept is that your child is gonna get it and they are gonna build immunity to it.  Why not speed along that process and increase the probability of encountering the virus?

Active Acquired

You are also speed up the process of encountering an antigen by vaccinations. Vaccines work by introducing antigens—parts of pathogens—into the body to provoke a first immune response without causing illness.  You don’t get the bacteria itself, the virus itself, or any other pathogen.  You get an attenuated pathogen that is all cut up into pieces. On some of those pieces are the immune-response provoking epitope of whatever it is you are being vaccinated against. 

The MMR vaccine (measles, mumps, rubella) contains proteinsLarge molecules made of amino acids with various functions in the body. from these viruses. However, it does not include the entire pathogen, ensuring no infection occurs. Vaccines mimic the first response, triggering the immune system to create memory cells. This is why people who receive vaccines often feel mild symptoms—it’s their immune system mobilizing.