The most numerous WBC is the a. eosinophil, b. neutrophil, c. monocyte, d. lymphocyte.

Video transcript

Welcome back everyone. Which type of white blood cell is involved in the immune response against parasitic infections and allergic reactions. We've got choice. A eosinophil choice B, basophil C monocyte and DB lymphocyte. Let's start by creating two categories. The first being parasitic infections and the second category being an allergic attack. So we're going to need to list the given light blood cells as far as which apply to each of our categories. So let's start with choice. A eosinophil recall that they are particularly effective against parasitic infections. And for that reason, we'll list eosinophils under this category with A plus sign and recall that they have a specialized role in the immune response towards multicellular parasites. And this is because eosinophils can release toxic substances via granule proteins on their surface that can attach to the surface of the parasite and effectively eliminate them. We can also list eosinophils under the allergic attack category. And this is because recall that eosinophils are capable of producing ig antibodies specific to a given allergen affecting an individual in order to provide an immune response. So we can place a plus sign here under that category. And we would place a check mark by choice. A because it appears that eosinophils can directly address both parasitic infections and allergic attacks. Now, we have choice. B basophils. Let's start with listing basophils under the allergic attack category. And this is because they are capable of releasing histamine and other inflammatory chemicals that are released during an allergic attack. And this leads to the uncomfortable symptoms associated with allergies, like itching, swelling and redness. And these responses are part of the body's defense mechanisms against the allergen which overall causes inflammation. So let's place a plus sign for basophils under the allergic attack category. And with regard to the parasitic infection category, we will list basophils with a minus sign because they do not play a direct role to address via an immune response, parasitic infections. Because as we stated, eosinophils are the primary cell type to address that. So we can rule out choice B for that reason because we need a white blood cell that can address directly both of these categories. Now, moving on to choice C monocyte. Now, this type of white blood cell can be guided by chemical signals from cytokines, growth factors and other molecules. And that allows them to differentiate into the two following categories as either primarily macrophages or also dendritic cells. And because they will primarily differentiate into macrophages. So we'll place number one there recall that macrophages are a white blood cell type that can engulf pathogens present in the body to eliminate them via phagocytosis, antigen presentation and activating other immune cells. And for that reason, monocytes do not play a direct role during parasitic infection. So we'll place a minus sign for monocytes in that category, as well as do monocytes will not play a direct role in allergic attacks, will also not include them in that category and will give them a minus sign. So overall monocytes have an indirect role in both of these categories. And we can rule out choice C for that reason. And last, we are left with choice BB sorry choice DB lymphocyte. So this is also known as B cells, which we should recall play an essential role in the adaptive immune response. And this is because B cells or B lymphocytes are capable of producing antibodies that are specific to fight against certain antigens which fall under the category of bacteria and viruses. So they will not have a direct role during parasitic infections. And for that reason, we have B lymphocytes with a minus sign under that category. And next, we should also recall that B cells are capable of producing IgE antibodies, but those are produced by B cells in response to or as a part of a larger and complex immune response rather than a direct attack on allergic reactions like eosinophils are capable of. And for that reason, we will list B lymphocytes with also a minus sign in the category of allergic attacks. So let's rule out choice D for that reason. And that leaves us with choice. A eosinophil as the only correct choice as an example of a white blood cell directly involved in the immune response against parasitic infections and allergic reactions. So I hope this helped and let us know if you have any questions.