Antibodies

What is Antibodies?

An antibody (AB), also known as an immunoglobulin (Ig), is a large, Y-shape protein produced by plasma cells that is used by the immune system to identify and neutralize pathogens such as bacteria and viruses. The antibody recognizes a unique molecule of the harmful agent, called an antigen, via the variable region. The production of antibodies is the main function of the humoral immune system.

Antibodies are secreted by cells of the adaptive immune system (B cells), and more specifically, differentiated B cells called plasma cells. Antibodies can occur in two physical forms, a soluble form that is secreted from the cell, and a membrane-bound form that is attached to the surface of a B cell and is referred to as the B cell receptor (BCR). The BCR is found only on the surface of B cells and facilitates the activation of these cells and their subsequent differentiation into either antibody factories called plasma cells or memory B cells that will survive in the body and remember that same antigen so the B cells can respond faster upon future exposure. In most cases, interaction of the B cell with a T helper cell is necessary to produce full activation of the B cell and, therefore, antibody generation following antigen binding. Soluble antibodies are released into the blood and tissue fluids, as well as many secretions to continue to survey for invading microorganisms.

Antibodies are glycoproteins belonging to the immunoglobulin superfamily; the terms antibody and immunoglobulin are often used interchangeably. The ability of antibodies to bind to FcRs helps to direct the appropriate immune response for each different type of foreign object they encounter. For example, IgE is responsible for an allergic response consisting mast cell degranulation and histamine release. IgE's Fab paratope binds to allergic antigen, for example house dust mite particles, while its Fc region binds to Fc receptor ε. The allergen-IgE-FcRε interaction mediates allergic signal transduction to induce conditions such as asthma.

Though the general structure of all antibodies is very similar, a small region at the tip of the protein is extremely variable, allowing millions of antibodies with slightly different tip structures, or antigen-binding sites, to exist. This region is known as the hypervariable region. Each of these variants can bind to a different antigen. This recombinational process that produces clonal antibody paratope diversity is called V(D)J or VJ recombination. Basically, the antibody paratope is polygenic, made up of three genes, V, D, and J. Each paratope locus is also polymorphic, such that during antibody production, one allele of V, one of D, and one of J is chosen. These gene segments are then joined together using random genetic recombination to produce the paratope. The regions where the genes are randomly recombined together is the hyper variable region used to recognise different antigens on a clonal basis.

Antibody genes also re-organize in a process called class switching that changes the one type of heavy chain Fc fragment to another, creating a different isotype of the antibody that retains the antigen-specific variable region. This allows a single antibody to be used by different types of Fc receptors, expressed on different parts of the immune system.

Questions and answers on "Antibodies"

I AM INTO MY 16TH WEEK OF PREGNANCY AND CURRENTLY ON 75MG ELTROXIN . MY LAST BLOODS WERE ON DATE 04/07/2012 FT4 14.2 RANGE (9.0-20.0), TSH 7.44 RANGE (0.35-4.94) - ON 50 MG ELTROXIN ON DATE 31/08/2012 FT4 14.2 RANGE (9.0-20.0) TSH 2.67 RANGE (.35-4.94) TPO 825.3 RANGE ( 5.6) - ON 75MG ELTROXIN. MY DOCTOR HAS RECOMMENDED THAT I INCREASE MY TABLETS TO 100MG FOR 4 DAYS AND 75 MG FOR 3 DAYS. I AM A LITTLE NERVOUS ABOUT THIS AS YOU WILL SEE FROM THE ABOVE READING MY INCREASE FROM 50 MG TO 75MG DECREASE MY TSH FROM 7.44 TO 2.67. WHAT DO YOU RECOMMEND. ALSO DO YOU THINK MY HIGH LEVEL OF ANTITHYROID ANTIBODIES WILL AFFECT MY PREGNANCY. MANY THANKS

doctor1 MD

Hello

Welcome

Yes it is better to increase the dose if antibodies are high as you have to maintain the level of TSH below 3 which you are maintaining already but high antibody titre indicates there is requirement of more dose.

Thyrowel tablet contains supplements and can be tried daily one tablet...

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my bloodgroup is ab-.i have a daughter 12yr old. their are antibodies in my blood i had lost one child due to that.i know what will happen if now i get pregnent.is blood transfusion in utres possible in deephospital ludhiana?age 37 weight 70kg height 5ft

doctor1 MD

There are chances of fetal affection if fetus is having positive blood group.
So when you conceive consult doctor immediately and get ICT Titres done.
Amniocentesis and fetal affection to be estimated.
Also MCA PSV to be done to see for fetal anemia and accordingly intra uterine blood transfusion...

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Hi, I am naveen..recently 3 months back i was diagns ed fkor tsh test..as I got alopecia areata ..my tsh level 3 months back is 7.33..now my tl3,t4 levels are normal..as they are between the numbers of normal..now tsh level is 3.19...antimirosom al antibodies are at level is 45 ..acoording to above given can you please tell my position..hypothroid I know anything more?..and lastly do I have hoshimoto thyroiditis .. as my present am a is 45 but my ama 1 and half. month back it is 77.3..please guide me

doctor1 MD

Good day,
Noted your concern. With the reports you have provided, you seems to have Hashimoto;s thyroiditis. Eventhough your TSH has settled now, there is a slight chance of progressing to Hypothyroidism in the future. You may have to repeat a Free T4 and TSH after 3-4 months.

Hashimoto's...

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hi i am AB- ve and my hubby is A+, i had aborted a child in 14th week of my pregnancy in 2007 and my hubby is away from me all these days used to come once in a month.now we are together and planning for baby, are there any chances antibodies present in my blood .can u please let me know which tests i have to under go and cost of tests and treatment.does that abortion show any negative effects on my future pregnancy or baby? please help me.

doctor1 MD

Welcome to Healthcare Magic
Usually after medical termination of pregnancy of the first child, an injection of RhoGam or Anti-D antibodies is needed to be given but this would matter only if the baby was also Rh -ve like you. Since you are planning pregnancy it is advisable to do Kleihauer Betke...

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2 years back i done h pylori treatment for pylori antibodies after checking blood for h pylori antibodies and result is positive.
now same problem facing like gas trouble and joint pain, again i checked h pylori antibodies but result is negative,
shall i use same treatment what done before H pylokit ?

doctor1 MD

Hi,
It is irrational to take treatment against a organism which is not present . It may led to resistant strain , superinfection , side effect of irrational drug ,....etc.
Epigastric burning pain , abdominal fullness , burping ,........are symptoms of gastritis and can occurs sure to various...

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what is tites for chicken pox - blood drawn/proof of immunity? i don t know what \

doctor1 MD

A proof of immunity means ,that we count the number of antibodies built up to protect you against the disease when stimulated by vaccine or by getting infected by the virus itself, so if it is high, that means that you have protection.

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yes, my question is why can't I get a kidney with high antibodies even though I've been told it is possible. I also have MGUS which seems to turn the doctors away from helping me push for a kidney. So I have these two major problems so is it still possible for me to get a kidney?

doctor1 MD

Yes dear it is possible by doing kidney transplant particularly by autologous kidney transplant. You should have same blood group to the donor one. Hope you get well soon. Thanks

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I had an std blood test done. I got a voicemail today saying that everything came back negative, except herpes simplex virus came back as me having antibodies. She said it was negative except I had antibodies so I had been exposed to the virus, but it was not active. I am wondering if this means I was merely at risk and dodged a bullet, or if i now HAVE herpes and it is just not on a flare up. I would like to know if I must now be on the lookout for flare ups, and if this is something I need to notify future partners of, or if I just dodged a bullet.

doctor1 MD

Hello. Thank you for writing to us at healthcaremagic

The test result suggests that you are infected with the virus, though you don't show any active lesions of it.
Herpes virus once acquired stays inside the body for the rest of life.
The virus stays dormant inside the body. However, from time...

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hello doc. my blood group is a- and my husband s a+ i mm 20 weeks pregnant what type of injection shuld i take to avoid any type of complications during delivery?

doctor1 MD

Dear upasana
Sometimes if a woman is pregnant with a Rhesus positive baby, and she is Rhesus negative, then soemthing called Rhesus (Rh) Incompatibility can occur. This means that you may produce antibodies against the foetus' blood and complications can occur.
It is important that the hospital...

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when should hiv test carried out after sex

doctor1 MD

In the vast majority of cases, the standard test that will be offered at an HIV testing centre will be an HIV antibody test. The HIV antibody test looks for antibodies to the virus in a person's blood. For most people these antibodies take 6 weeks to 3 months to develop. In very rare cases, it...

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Recent questions on  Antibodies

doctor1 MD

I have had pain in left flank area for months.Pain is mostly upon palpation though it does throb sometimes, and the affected area is growing. Also having digestive issues,polyneuropathy,chronic anemia & Vitamin D deficiency, sciatica, EDS, and antibodies suggesting SLE -to name a few other things going on.I have an impressive list of specialists I see, but no one has an answer for this one yet. Any thoughts? Thank you for your time.

doctor1 MD

I have been having body pain, shortness of breath, extreme fatigue. There is small amount of fluid on lung, swollen left kidney, nodules on lungs and something on liver. I have had ct scans and mri's on lungs, liver and kidneys, but no conclusion. I am now having extensive bloodwork done. ie; lupus antibodies, AST, Total protein, CA 125, ESR - ANA.

doctor1 MD

hi, i have been experencing yellow eyes and my urine is tea color dark. The docor did an ultrasound on my liver and he said it was enlarged and my antibodies in my blood is high. And when you push in on my liver it is really tender. My ast and alt is up in my blood test. Gallstones run in my family also. what do you think

doctor1 MD

my bloodgroup is ab-.i have a daughter 12yr old. their are antibodies in my blood i had lost one child due to that.i know what will happen if now i get pregnent.is blood transfusion in utres possible in deephospital ludhiana?age 37 weight 70kg height 5ft

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Hi, I am Dr. Andrew Rynne (Family Physician). I will be guiding you through the process. Please write your question below.

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