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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

why is DNA a genetic material
Mcbeth Reply
DNA is genetic material because it contains chromosome contains the traits which includes characters and behavioral characteristics
chima
what is infection prevention
Muhammed Reply
good hygiene
Dhaqan
way of preventing disease causing germs
henry
maintenance of sterilization
Pooja
h
Faustina
describe the components of the epidemiology triangle
Muhammed Reply
Hai
Nantongo
hii
Md
where from you
Md
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Md
you
Md
Hello friend
effiong
How are you people doing
effiong
أ‌) Host factor ب) pathogen ج) environment
Widad
Hello
Kofi
Hi
Widad
hey hi
kalai
The epidemiologic triangle is made up of three parts: agent, host and environment
Princess
what are the fluids used in biochemistry Lab used to diagnose diseases
Jb Reply
fadumo qule a gemil3
fadumo Reply
Faadum mahamud disease micro biology
fadumo
makuway diinkaraan suaalo
fadumo
history of microbiology
Balqees Reply
Penicillin is caused by what microorganism
Balqees
Penicillin is caused by what microorganism
Balqees
penicillium notatum
Pooja
M sorry I mean penicillin is caused by what Fungi
Balqees
penicillium fungi
Pooja
mention 5 characteristics of prokaryotic cell and also 5 characteristics of euryotic cell
Grace Reply
PROKARYOTES _ does not have nucleus _does not have membrane bound organels like eukaryotes -does not have endoplasmic reticulum _does not have a mitchochondrion _it have plasmid instead of chromosome EUKARYOTE S _have true nucleus _have all membrane bound organels _have mitochondria have
Pooja
continuation _have endoplasmic reticulum _have chromosomes does not have plasmid
Pooja
antigenisity define
kalai
explanation of spores
nahida Reply
what specific types of biological macromolecules do living things require?
Jonathan Reply
define spores its classification
nahida
define spores its structure and classification
nahida
what is a complement
Alecia Reply
something which completes or combine with something else to make it complete.
Kosi
hello
Kosi
medical microbiology
Kosi
you?
Kosi
hi
Amina
Guys who's doing nursing in here
Mumba
I have a question
Mumba
what's the importance of microbiology in nursing
Mumba
yah
Mumba
wow..nice meeting you
Kosi
thanks
Mumba
for
Mumba
anytime
Mumba
microbiology also important for understanding the communicable or non-communicable disease in our hospitals...which is very important for patients and healthy people.
Kiran
what is a microbial flora
Chetan
normal microbial flora
Chetan
Definition of microbiology?
Mohamed Reply
study of microorganisms is known as microbiology
Pooja
no
Mumba
microbiology is the study of small or minute organisms that cannot be seen with our naked eyes but with the aid of a microscope
Mumba
write and explain the infection chain of 6 common disease infections
Adjowa Reply
diphtheria. dysentery. bubonic plague. pneumonia. tuberculosis. typhoid. typhus. Aug 22, 2017
shamim
good afternoon
Dasaah
OK
Dasaah
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fine
Dasaah
which bacteria can be isolated from abattoirs ( slaughter houses).
Omoja
bacteria that csn be isolated from abattoirs are- Clostridium Bacteroides Desulfobulbus Desulfomicrobium Desulfovibrio
Yashkin
what is a microscope
Louise Reply
Is an instrument used to magnify object which can not be seen with our naked eyes.
Mohamed
are virus host specific?
koguriyem Reply
are viruses effective in small dose?
koguriyem
structure of the bacteria
Eunice Reply

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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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