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Learning objectives

  • Compare the method of development, use, and characteristics of monoclonal and polyclonal antibodies
  • Explain the nature of antibody cross-reactivity and why this is less of a problem with monoclonal antibodies

Part 1

In an unfortunate incident, a healthcare worker struggling with addiction was caught stealing syringes of painkillers and replacing them with syringes filled with unknown substances. The hospital immediately fired the employee and had him arrested; however, two patients that he had worked with later tested positive for HIV.

While there was no proof that the infections originated from the tainted syringes, the hospital’s public health physician took immediate steps to determine whether any other patients had been put at risk. Although the worker had only been employed for a short time, it was determined that he had come into contact with more than 1300 patients. The hospital decided to contact all of these patients and have them tested for HIV.

  • Why does the hospital feel it is necessary to test every patient for HIV?
  • What types of tests can be used to determine if a patient has HIV?

Jump to the next Clinical Focus box.

In addition to being crucial for our normal immune response, antibodies provide powerful tools for research and diagnostic purposes. The high specificity of antibodies makes them an excellent tool for detecting and quantifying a broad array of targets, from drugs to serum proteins to microorganisms. With in vitro assays , antibodies can be used to precipitate soluble antigens, agglutinate (clump) cells, opsonize and kill bacteria with the assistance of complement, and neutralize drugs, toxins, and viruses.

An antibody’s specificity results from the antigen-binding site formed within the variable regions —regions of the antibody that have unique patterns of amino acids that can only bind to target antigens with a molecular sequence that provides complementary charges and noncovalent bonds. There are limitations to antibody specificity, however. Some antigens are so chemically similar that cross-reactivity occurs; in other words, antibodies raised against one antigen bind to a chemically similar but different antigen. Consider an antigen that consists of a single protein with multiple epitopes ( [link] ). This single protein may stimulate the production of many different antibodies, some of which may bind to chemically identical epitopes on other proteins.

Cross-reactivity is more likely to occur between antibodies and antigens that have low affinity or avidity . Affinity, which can be determined experimentally, is a measure of the binding strength between an antibody's binding site and an epitope, whereas avidity is the total strength of all the interactions in an antibody-antigen complex (which may have more than one bonding site). Avidity is influenced by affinity as well as the structural arrangements of the epitope and the variable regions of the antibody. If an antibody has a high affinity/avidity for a specific antigen, it is less likely to cross-react with an antigen for which it has a lower affinity/avidity.

Questions & Answers

what is gram staining
Nankya Reply
microbiology?
Bekka
Tell u only
Balu
It's technique to differentiate bacterial species.The method is discovered by Hans Christian Gram. The bacteria is differentiated as gram positive and gram negative on the basis of peptidoglycan layer which is present in cell wall. The gram positive have peptidoglycan layer.
shamali
What is study of morphology ? and it's classification
Maryam
what makes a student to forget what he or she has been taught with easily and how can he or she cope up with it
Samson Reply
to be in touch with subject will help to cope up with the learning life long and also interest matters for subject
shriya
Constant review. And don't worry if you do forget something you always have the option to study it again. Each time you study a certain topic the more it make sense and the more it becomes something natural rather than brute memorization.
Abdi
the cause are many 1.lack of interest . 2. poor attitude to the subject. how can he cope up 1. falling in love with the subject . 2. making it part of you at all times and having determination
Ikilai
understanding the concept and relating whatever course of study with something in his/her day to day activities (i.e in which you are more conversant with in your life).
Kamaluddeen
how many types of cross matching method
umesh
which disease is caused by vicera zoster virus
Timaka Reply
chicken pox
Osuoha
Patients with disseminated herpes zostermay present with severe abdominal pain that results from visceral involvement of varicella-zoster-virus infection. In immunocompetent individuals herpes zoster usually is a localised illness, affecting the skin of one or two adjacent dermatomes.
Kamaluddeen
Actually, it is severe abdominal pain thanks
Osuoha
what causes inflammation of the lung?
Samson
what causes the fungi infection of the vigina
Estar Reply
what causes the fungi infection of the vagina?
Estar
poor hygiene of the area and unprotected sex with infected partner
Kamaluddeen
poor hygiene,some times having sex with infected person or when normal flora enters in the vagina
Ikilai
unprotected sex and poor hygiene are the major but keep in mind that there are some other minor causes also
Samson
what brings about dirt in blood
Sumaiyah Reply
So many factors might be the cause viz. Defects of blood capillaries and certain organs like the liver, the kidneys e.t.c
MOHAMMED
with the above any infection of the body easily enters the bloodstream.
MOHAMMED
there may be fevers which cause septicemia
Ikilai
even taking drug, and eating junk foods .
Ikilai
drinking contaminated water and taking drugs which contains chemical and afterwards they gets absorbed in yo the blood stream
Samson
write a essay about gene library's
anaparthi Reply
Structure of bacteria
Maggy Reply
Outline the classification of viruses according to morphology, nucleic acid, type of diseases, antigenic reaction
chilufya Reply
who is da father of microbiology
Mukomya Reply
Lucie pasture
Felicity
Father of microbiology is Anton von Leuuwenhoek
Anshika
mean Luice pasture the father of microbiology
Felicity
Luice pasture is the father of industrial microbiology
Anshika
who is the father of surgery
Talemwa
father of surgery is Sushruta
Agyekum
sushruta is the father of surgery
Ven.phumie
he Anthony van Lee wen hock
Ikilai
who is the father of medical microbiology
Naveen
he is Anthony van Lee wen hock
Ikilai
Anthony van Lee wen hook
Kamaluddeen
where would we be without microbes
Jessa Reply
nowhere because our body alone also contain billions of microbes.
Edward
in the dreams
Abid
Bangladeshi people's body contain thrice the amount of microbes than regular people.
IamTheMegaExploder
sure?
Kamaluddeen
yah
Kamran
why it was like that
Mمهazn
no where
Mukomya
cocci which are arranged in pairs are called?
umesh
diplococci
vijaya
Cocci are bacterias
Anshika
fimbriae is an organ of ?
umesh
what is the choma like vrius?
PRALHAD
Vibrio cholarea
Kamaluddeen
outline the classification of viruses
chilufya
Fimbriae z an organ of bacteria
Maggy
Antoni van Leeuwenhoek, the father of micro biology
Yang
concept of primary& secondary metabolism
yamini Reply
who is the father of microbiology
imran Reply
Louis pasture is a father of modern microbiology
Bharat
anton van leuwen kook
Kavi
anton van is father of ancient microbiolgy
Bharat
Antonie van Leeuwenhoek
Bharat
g
Red
Louis pasture
Atar
what can cause serious stomachache after treating ulcer and typhoid and symptoms persist to leave.
Ven.phumie
Anthony van
Nankya
what is lumbar puncture
amulya Reply
To get the cerespinalfluid
Alphonsia
what is the role of glutamic acid in consideration to ulcer healin
Hyrin Reply
what is role of glutamic acid in peptidoglycan
Pooja Reply
what's the name of Greek word were nursing came from?
Joyce
Take care.
Alphonsia
thanks
Joyce
glutamic acid helps in synthesis of protein
Ganesh
i want some explantion on gram staining
Nankya
gram (+ve) or gram(-ve)
Atar
gram stain is defined as identification methods for bacteria
vijaya
Gram stain or Gram staining, also called Gram's method, is a method of staining used to distinguish and classify bacterial species into two large groups (gram-positive and gram-negative). The name comes from the Danish bacteriologist Hans Christian Gram, who developed the technique.
Atar

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Source:  OpenStax, Microbiology. OpenStax CNX. Nov 01, 2016 Download for free at http://cnx.org/content/col12087/1.4
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