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IgG    is a major antibody of late primary responses and the main antibody of secondary responses in the blood. This is because class switching occurs during primary responses. IgG is a monomeric antibody that clears pathogens from the blood and can activate complement proteins (although not as well as IgM), taking advantage of its antibacterial activities. Furthermore, this class of antibody is the one that crosses the placenta to protect the developing fetus from disease exits the blood to the interstitial fluid to fight extracellular pathogens.

IgA    exists in two forms, a four-chain monomer in the blood and an eight-chain structure, or dimer, in exocrine gland secretions of the mucous membranes, including mucus, saliva, and tears. Thus, dimeric IgA is the only antibody to leave the interior of the body to protect body surfaces. IgA is also of importance to newborns, because this antibody is present in mother’s breast milk (colostrum), which serves to protect the infant from disease.

IgE    is usually associated with allergies and anaphylaxis. It is present in the lowest concentration in the blood, because its Fc region binds strongly to an IgE-specific Fc receptor on the surfaces of mast cells. IgE makes mast cell degranulation very specific, such that if a person is allergic to peanuts, there will be peanut-specific IgE bound to his or her mast cells. In this person, eating peanuts will cause the mast cells to degranulate, sometimes causing severe allergic reactions, including anaphylaxis, a severe, systemic allergic response that can cause death.

Clonal selection of b cells

Clonal selection and expansion work much the same way in B cells as in T cells. Only B cells with appropriate antigen specificity are selected for and expanded ( [link] ). Eventually, the plasma cells secrete antibodies with antigenic specificity identical to those that were on the surfaces of the selected B cells. Notice in the figure that both plasma cells and memory B cells are generated simultaneously.

Clonal selection of b cells

This flow chart shows how the clonal selection of B cells takes place. The left panel shows the primary response and the right panel shows the secondary response.
During a primary B cell immune response, both antibody-secreting plasma cells and memory B cells are produced. These memory cells lead to the differentiation of more plasma cells and memory B cells during secondary responses.

Primary versus secondary b cell responses

Primary and secondary responses as they relate to T cells were discussed earlier. This section will look at these responses with B cells and antibody production. Because antibodies are easily obtained from blood samples, they are easy to follow and graph ( [link] ). As you will see from the figure, the primary response to an antigen (representing a pathogen) is delayed by several days. This is the time it takes for the B cell clones to expand and differentiate into plasma cells. The level of antibody produced is low, but it is sufficient for immune protection. The second time a person encounters the same antigen, there is no time delay, and the amount of antibody made is much higher. Thus, the secondary antibody response overwhelms the pathogens quickly and, in most situations, no symptoms are felt. When a different antigen is used, another primary response is made with its low antibody levels and time delay.

Questions & Answers

describe the muscles found in the heart
Atotwe Reply
myocardial
Kenndy
thank you very much
Atotwe
asalamu aleikum
Cabdala
what is a muscular system and details about it
Jackson Reply
what is the type of homones responseble for blenking of eyes
Moses Reply
what are the functions of cell?
Keyirangzile Reply
how does the femur act as a lever?
Mutoni Reply
what is stumac
Abdussalam Reply
What is phagocytosis
Mohamed Reply
Phagocytosis, process by which certain living cells called phagocyte
Sadashiv
It is the process that is carried out by the immune system of the body, that certain specialized immune cells (macrophages, Nks, dendritic cells, etc) that engulf and neutralize the foreign substances that invades the body.
Wesley
So that they can be predicate out of the body.
Wesley
phagocytosis is the process by which living cell or yh plasma membrane engulf large molecules into it internal environment ... it also known as food feeding
Boateng
all that you are say what does it mean?
Dzah
simply is the way the immune system fights foreign bodies by engulfing them..
Dzah
by the help of the immune cells...
Dzah
what are the six types of connective tissues
Athieno Reply
loose and dense , cartilage and bone , blood and lymph
Queen
describe the structure of the liver
Atwebembeire Reply
what is specific name for spinal cord
Stanley Reply
what is the best description for skeletal muscular
Stanley
what is the best description for skeletal muscular
Stanley
costs of bones of skeleton, their joint s and voluntary
grace
what are examples of long bones
grace
example of long bones will be the femur tibia and humerus and even radius
Nina
so basically long bones are mostly in you hands and feets
Nina
skeletal muscular are voluntary and are attached to the bone by tendon which help maintain the posture and position of the body and it also protects internal organs in the abdominal region
Nina
The specific name for spinal cord is coccygeal segment
Sandra
what are the hormones responseble for blenking of eyes.
Moses
Smallest unit of life
Kimberly Reply
cell
Adnan
The cell is the smallest structural and functional unit of living organisms, which can exist on its own. Therefore, it is sometimes called the building block of life. Some organisms, such as bacteria or yeast, are unicellular—consisting only of a single cell—while others, for instance, mammalians, a
Adnan
cells are the building blocks of life
Stanley
Describe the complications of fracture
Zaifa Reply
functions of connective tissue
renah Reply
binding and structural support protection Insulation Transport of materials
Priyantha
what is a local potential
Nandi Reply
potential of neurons
vipin
response of neurons against sodium ion Chanel
vipin
The resting membrane potential of a neuron is about -70 mV (mV=millivolt) - this means that the inside of the neuron is 70 mV less than the outside. At rest, there are relatively more sodium ions outside the neuron and more potassium ions inside that neuron.
Adnan
what is tissues
Addai Reply
are groups of specialized cell that perform they same activity
Deng
a group of specialized cells of the same structure and function
Malenga
a group of specialized cells that have the same structure and perform the same function
Cantiago
tissue is a group of specialised cells performing similar functions and are of the same embryonic origin
Maura
group of specialized cells that have similar structure and act together to perform a specific function
esekon
a group of specialised cell which has same function
Grace
a group of specialized cells that perform the same function.
faiz
group of one or more cell types that specialized to perform a particular function.
Priyantha

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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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