Passive antibody therapy
Antibodies are gamma globulin proteins that make up 20% of the plasma proteins.
Immunoglobulins can be induced actively in the host (through vaccines for example), or acquired passively from other people’s plasma that have the needed antibodies.
1 person may donate plasma that will be useful for about two doses of treatment for COVID-19. It is not sufficient. So, the process is slow.
Passive immunity is used to neutralize toxins of diphtheria, tetanus, botulism. We also have passive antibodies for viruses like rabies, hepatitis A and B viruses, etc.
Plasma contains fibrinogen (for clotting) and albumin (to keep plasma in the blood vessels.) Plasma transports proteins, nutrients, antibodies, etc. to the tissues of the body. Plasma will also wash away the waste products produced by the cells.
Serum on the other hand is plasma minus the clotting factors. Serum is obtained after blood clotting. Serum contains the antibodies, hence one of its use is to test for antibodies.
Antibodies are IgG, IgM, IgA, IgD, and IgE (GAMED)
Immunoglobulins (Igs) act to neutralize the toxins. They help opsonize the pathogens. Activate complement system. And, they help prevent the attachment of the pathogens to mucosal surfaces.
Monoclonal vs. polyclonal antibodies.
Immunoglobulins are glycoproteins. They consist of a light (L) chain, and a heavy (H) chain. Simplest antibody molecule is a Y shaped complex.
Light chains’ heavy region can be either kappa or lambda. But, in one molecule of an immunoglobulin only one type of light chain will be present (either containing kappa or lambda.)
Light chains have one variable and one heavy domain.
Heavy chains have one variable and three or four heavy domains. IgG and IgA have 3, IgM and IgE have 4.
Variable regions of both the chain are for the antigen binding.
Constant region of the heavy chain is for the biological functions like binding to a cell/surface and complement activation.
GM makes classic cars. IgG and IgM activate complement.
IgG looks pregnant. It passes through the placenta.
IgA is always away to the outdoors. It sits in the surface mucosal fluids.
IgD is only a receptor on the B cells.
IgE is on the mast cells and takes parts in allergies. We don’t want too much of this unless there are worm infections.
IgG also helps opsonize (see it has a pac man like open mouth? Phagocytes have receptors for the IgG heavy chains.)
IgM can activate complement. Which in turn produces C3b which is also a opsonizing molecule. Because phagocytes also have the receptors for C3b.
IgM is usually found as five molecules joined with a J chain. Hence, it has ten binding sites (two sites on each protein.) It is the most efficient immunoglobulin and is produced as the first response.
Genes to form the heavy chains are arranged as (VVVV-D-JJJJ-HMHDHGHEHA)
Genes to form the light chains are arranged as (VVVV-D-JJJJ)
All B cells first produce IgM and IgD. Then the class switching allows them to produce IgG, IgE, and IgE. Various cytokines can influence the switching to various Immunoglobulin types.
Once a specific heavy chain has been spliced out, that immunoglobulin cannot be made any more by this B cell.
Every new encounter with the antigen improves the response. This is because of somatic hypermutation and affinity maturation.
FDA approves blood plasma therapy
FDA has a form 3926 to fill and send. Response within 4 to 8 hours.
Emergency response needed, call operations at 1-866-300-4374 to seek verbal authorization.
https://www.uscovidplasma.org/
FDA will send an IND number (investigational new drug number.)
First patient to receive plasma in Colorado is a doctor (Dr. Michael Leonard)
Mt. Saini
Dr. Jeffery Jhang. Using plasma infusion.
Mayo clinic
Dr. Michael Joyner
Takeda pharma making this product
A science journalist's take
In this video we will learn about :
1. Authorization of convalescent plasma use by WHO.
2. Rationale of convalescent plasma use fpr COVID-19 patients.
3. Antibodies production in recovered patient.
4. Immune response of a convalescent plasma.
5. Efficacy of convalescent plasma therapy.
No credit card information needed.
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