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Primary and secondary antibody responses

This graph shows the antibody concentration as a function of time in primary and secondary response.
Antigen A is given once to generate a primary response and later to generate a secondary response. When a different antigen is given for the first time, a new primary response is made.

Active versus passive immunity

Immunity to pathogens, and the ability to control pathogen growth so that damage to the tissues of the body is limited, can be acquired by (1) the active development of an immune response in the infected individual or (2) the passive transfer of immune components from an immune individual to a nonimmune one. Both active and passive immunity have examples in the natural world and as part of medicine.

Active immunity is the resistance to pathogens acquired during an adaptive immune response within an individual ( [link] ). Naturally acquired active immunity, the response to a pathogen, is the focus of this chapter. Artificially acquired active immunity involves the use of vaccines. A vaccine is a killed or weakened pathogen or its components that, when administered to a healthy individual, leads to the development of immunological memory (a weakened primary immune response) without causing much in the way of symptoms. Thus, with the use of vaccines, one can avoid the damage from disease that results from the first exposure to the pathogen, yet reap the benefits of protection from immunological memory. The advent of vaccines was one of the major medical advances of the twentieth century and led to the eradication of smallpox and the control of many infectious diseases, including polio, measles, and whooping cough.

Active versus Passive Immunity
Natural Artificial
Active Adaptive immune response Vaccine response
Passive Trans-placental antibodies/breastfeeding Immune globulin injections

Passive immunity arises from the transfer of antibodies to an individual without requiring them to mount their own active immune response. Naturally acquired passive immunity is seen during fetal development. IgG is transferred from the maternal circulation to the fetus via the placenta, protecting the fetus from infection and protecting the newborn for the first few months of its life. As already stated, a newborn benefits from the IgA antibodies it obtains from milk during breastfeeding. The fetus and newborn thus benefit from the immunological memory of the mother to the pathogens to which she has been exposed. In medicine, artificially acquired passive immunity usually involves injections of immunoglobulins, taken from animals previously exposed to a specific pathogen. This treatment is a fast-acting method of temporarily protecting an individual who was possibly exposed to a pathogen. The downside to both types of passive immunity is the lack of the development of immunological memory. Once the antibodies are transferred, they are effective for only a limited time before they degrade.

Immunity can be acquired in an active or passive way, and it can be natural or artificial. Watch this video to see an animated discussion of passive and active immunity. What is an example of natural immunity acquired passively?

T cell-dependent versus t cell-independent antigens

As discussed previously, Th2 cells secrete cytokines that drive the production of antibodies in a B cell, responding to complex antigens such as those made by proteins. On the other hand, some antigens are T cell independent. A T cell-independent antigen    usually is in the form of repeated carbohydrate moieties found on the cell walls of bacteria. Each antibody on the B cell surface has two binding sites, and the repeated nature of T cell-independent antigen leads to crosslinking of the surface antibodies on the B cell. The crosslinking is enough to activate it in the absence of T cell cytokines.

A T cell-dependent antigen    , on the other hand, usually is not repeated to the same degree on the pathogen and thus does not crosslink surface antibody with the same efficiency. To elicit a response to such antigens, the B and T cells must come close together ( [link] ). The B cell must receive two signals to become activated. Its surface immunoglobulin must recognize native antigen. Some of this antigen is internalized, processed, and presented to the Th2 cells on a class II MHC molecule. The T cell then binds using its antigen receptor and is activated to secrete cytokines that diffuse to the B cell, finally activating it completely. Thus, the B cell receives signals from both its surface antibody and the T cell via its cytokines, and acts as a professional antigen-presenting cell in the process.

T and b cell binding

This diagram shows the binding of a B cell and a T cell.
To elicit a response to a T cell-dependent antigen, the B and T cells must come close together. To become fully activated, the B cell must receive two signals from the native antigen and the T cell’s cytokines.

Chapter review

B cells, which develop within the bone marrow, are responsible for making five different classes of antibodies, each with its own functions. B cells have their own mechanisms for tolerance, but in peripheral tolerance, the B cells that leave the bone marrow remain inactive due to T cell tolerance. Some B cells do not need T cell cytokines to make antibody, and they bypass this need by the crosslinking of their surface immunoglobulin by repeated carbohydrate residues found in the cell walls of many bacterial species. Others require T cells to become activated.

Immunity can be acquired in an active or passive way, and it can be natural or artificial. Watch this video to see an animated discussion of passive and active immunity. What is an example of natural immunity acquired passively?

Breastfeeding is an example of natural immunity acquired passively.

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Questions & Answers

why are postsynaptic ganglionic neurons unmyelinated
Callie Reply
anatomy defination in urdu
Atif Reply
human body largest organ.....
jasveer Reply
liver
JOY
liver
Lem
Skin
amen
lungs
Zamiir
liver and skin
Marina
skin
brian
by mass is liver but externally is de skin
Kumsah
all answers Are correct
brian
no
Rehman
liver is the largest gland of the body but skin is the largest organ of the body
Rehman
so please what is the answer now
Marina
afcous skin.because difference between Gland and organ
Safiya
Only the skin
Williams
The largest organ is the skin and the liver is a gland
Williams
skin is the largest organ of the body
Denis
liver
julie
it's the skin
trinna
skin 100%
Mallikharjun
largest organ- liver largest system- Skin
Shahriar
largest organ is skin because it covers the rest of the organs
Syed
liver right answers
nisha
liver
Justine
skin
Areej
liver is largest gland
Areej
skin is largest organ liver is largest gland femur is largest bone thyroid gland is largest endocrine gland seratus muscle is largest muscle
Tanveer
sciatic nerve is largest nerve
Tanveer
portal vein is largest vein
Tanveer
GIT is largest tube in body
Tanveer
explain about cerebrum cereblum and pons medulla
Tanveer
Nervous system anotomy and physiology
Tanveer
skin is the human body's largest organ
Kimbley
@Tanveer, the cerebrum consists of the cerebral cortex, corpus callosum, hippocampus, and basal ganglia. The cerebellum is located inferior to the occipital lobe. The pons and medulla are part of the lower brainstem.
Carmelo
The cerebral cortex are divided into 4 lobes and control functions such as: thinking, learning, speech, sensory perception, motor functions, hearing and vision, etc. The cerebral cortex is mainly present only in mammals due to evolution. The hippocampus plays a main role in memory formation.
Carmelo
The cerebellum works together with the motor cortex and other parts of the brain to coordinate and fine tune muscular activity. The pons and medulla control autonomic functions such as: sleep, respiration, swallowing, vomiting, heart rate, vasomotor control and more other things.
Carmelo
skin hai friend
Tilak
what is the biliary tract
famuyiwa
The biliary tract involves the liver, gallbladder, and bile duct. Certain liver cells (hepatocytes) synthesize bile salts derived from cholesterol in response to Secretin hormone. The gallbladder stores the bile. Gallbladder releases bile to the bile duct in response to Cholecystokinin hormone.
Carmelo
The role of bile is to emulsify fats so that they can be easily broken down and absorbed by the enterocytes into the lacteal vessels.
Carmelo
what is the difference between negative feedback loop and positive feedback loop
famuyiwa
what is cholesterol
Kay
unsaturated fats
famuyiwa
so what is the main purpose of anomaly
Kay
Cholesterol is a waxy substance your body uses to protect nerves, make cell tissues, and produce certain hormones.
Favour
Cholesterol is a type of lipid and it is a nonpolar molecule. The molecule is mainly composed of hydrocarbon chains. Cholesterol is synthesized in the smooth endoplasmic reticulum in eukaryotic cells, and is the main building block material for steroids, Vit D, and bile salts.
Carmelo
Negative feedback loop reverses any change back to its set point. For ex, when your internal body temperature rises above 98.6 F, your hypothalamus triggers your dermal blood vessels to dilate and activate sweat glands through sympathetic motor nerves so you can sweat and cool off back to 98.6 F.
Carmelo
Positive feedback loop amplifies a change. For ex, during labor, oxytocin is released continuously in a positive feedback loop from the posterior pituitary gland to stimulate contraction of the myometrium so the baby can come out.
Carmelo
define homeostasis and explain it's importants
Adusei Reply
define the important life processes of humans
Adusei
how the bone marrow transplantation is done?
Tanveer
what is homeostasis
julie Reply
internal temperature of body
Sanket
Homeostasis is the internal constancy in which your body tries to maintain for optimal cellular functioning. For example, your body tries to maintain an internal body temperature of about 98.6F for optimal functioning of your body.
Carmelo
If a prolonged lost of homeostasis occurs, death of the organism will be the outcome.
Carmelo
Another example of homeostasis is that your body tries to maintain a specific blood sugar level, so that your cells can undergo constant cellular respiration and keep you alive.
Carmelo
homeostasis is the fairly constant internal changes of an environment (your internal environment).The temperature of a body must be kept between the range of 37.5°c
raphael
which tissue is more sensitive
Rit Reply
to what?
Lari
explain types of hypertension
Juli Reply
What is bulbar paralysis?
Roshni Reply
how can make penis larger
Marwat Reply
what is the stimuli initiates the control of erythropoiesis?
Ok Reply
oxygen
Liyungu
Erythropoietin, a hormone synthesized and released by the kidneys stimulate erythropoiesis in red bone marrow. When an Individual loses blood (hemorrhage) and the concentration of RBCs or oxygen decreases, erythropoitein will be released.
Carmelo
how lymph is from
Hafsa Reply
Lymph is essentially interstitial fluid that ends up in the lymphatic vessels that didn't go back into the venules. Lymph is composed of the same components as your blood plasma which contains water, solutes, oxygen, CO2, foreign particles such as toxins, bacteria and viruses.
Carmelo
what is the cause of twins
Clarus
The cause of identical twins is when a single fertilized egg undergo mitosis (splits in two) . As a result, both eggs now have the same genetic information, therefore producing two identical twins.
Carmelo
how structure and function relate to each other?
Garmai
This is a very important rule in Anatomy and Physiology. The structure of a cell, tissue, or organ will tell you a lot about it's function.
Carmelo
For example, simple columnar cells (enterocytes) in the villus present in the duodenum of the small intestine contain microvilli. Microvilli are finger like projections of the cell membrane (produce by the cytoskeleton)that increase the surface area for absorption of nutrients into the enterocytes.
Carmelo
The main role of these enterocytes is to absorb. Therefore, having Microvilli as a structure relates to its function.
Carmelo
@ Carmelo thanks for the answer.
Garmai
welcome
Carmelo
what is the difference between negative feedback loop and positive feedback loop
famuyiwa
what is anatomy
Kamran Reply
is simply defined as the stody of internal and external structure of human body and the relationships between the body part.
Surajo
Anatomy Is The Study Of The Structure Of The Human body
Dennis
anatomy is the science that deals with the study of the body structure
Vida
what is stress hyperglycaemia and Pathophysiology
amani
Hyperglycemia is the term used when somebody is in a state of high blood sugar levels. For example, after you eat a meal with carbohydrates in it, (post-absorbptive state) your blood is hyperglycemic.
Carmelo
Pathophysiology is the study of how diseases function and cause abnormal functioning in the body. Usually pathophysiology is studied at a molecular/cellular level.
Carmelo
I meant to say absorbptive* state on explanation of hyperglycemia. Usually during post-absorbptive state your blood has low blood sugar levels.
Carmelo
Explain two best methods of avoiding pregnancies as adolescents
Bright
what is sex?
Soumyakanta Reply
Your biological sex is determined by your sex chromosome which is pair number 23. if you have a XX pair then you are a female. if you have XY pair then you are a male.
Carmelo
the sex chromosomes are called as allosome
Tanveer
True, the other 22 pairs are called autosomes :)
Carmelo
why the left hemisphere controls the right side body parts and right hemisphere controls the left side body parts?
Tanveer
because it is like that
Sherin
It has to do with how the neuronal pathway are intertwined to opposites sides of the body I think. A motor output from the left cerebral hemisphere (motor cortex) will end up stimulating your right side of the body.
Carmelo
brother Carmelo don't miander, sex ,it just the state of being a male or female
Liyungu
Your biological sex is tied to your DNA (genetic information). A male have testes and female have ovaries which are reproductive organs is tied to your genetic information (sex chromosome). If an individual feels like it is either a male or female is called gender identity.
Carmelo
thanks our beloved brother Carmelo
Liyungu
that's great learning something everyday
Tasheria
what is anatomy
Rohino
most blood enters the ventricle during what phase?
Tina Reply
rapid ejection
Tanveer
Most of the blood in the heart enters the ventricles during the diastolic phase.
Carmelo
ok
ren
which of the following is the types of personal protective equipment protects mucous membranes?
Garmai
Most (not all) mucous membranes secrete mucus because they contain goblet cells in between the epithelial tissue. Mucus coats the layers of epithelium and traps particles. The epithelial type is either stratified squamous, simple columnar, or pseudostratified columnar in mucous membranes.
Carmelo
Are you a professor Carmelo?
Sherin
No sir, I'm a nursing and biology student as well in university.
Carmelo
smart!
Sherin
thanks!
Carmelo
why the fever occurs if any injury or pain occurs
Tanveer
fever is de best indication to show there is an infection
Kumsah
what is the actual mechanism of fever
Tanveer
correct Tanveer, the normal internal body temperature is 98.6 Fareinheit. When the temperature rises above 100 fareinheit, it is usually an indication of infection.
Carmelo
White blood cells which protect you against foreign antigens become active and release cytokines (pyrogens) during infection which causes the hypothalamus to raise your internal body temperature.
Carmelo
thank you so much.really you are very intelligent.
Tanveer
thank you. you are very intelligent
Tanveer
the mechanism of fever appears to be a defensive reaction by the body against infectious disease. when bacteria or viruses invade the body and cause tissue injury one of de body immune system's responses is to produce pyrogen
Kumsah
Yes, the hypothalamus responds to pyrogens by raising your body temperature. The reason your hypothalamus does this is to stunt the growth and metabolism of whatever is causing the infection (bacteria, virus, fungi protozoa, etc.)
Carmelo
how the kidney transplantation is done
Tanveer
Which university are you studying?
Sherin
karnataka
Tanveer
and all of you ,university
Tanveer
Really so talented
Savita
I was asking Carmelo?
Sherin
Georgia State University.
Carmelo
oh nice! I'm in University of Texas
Sherin
nice!!!
Carmelo
vicious this is chaptare I reading 5day after
Taufik
pleas sir can u teach me
Taufik
not sure, can u help me?
Nichole
I'm in University of Technology, Jamaica
Nichole
why do you not helf me
Taufik
what difference exist between anatomy and physiology?
Collins Reply
Anatomy: study of the structure of the body parts and their relationship to one another
Shana
Physiology: Study of the function of body parts and how they work to carry out life-sustaining activities
Shana
physiology function and anatomy location
Bashir
anatomy refers to the study of the body parts and their relationship to each other while physiology deals with functioning of those body parts
Umutoni
Yes of course.In layman language Anatomy is study of internal organs, whereas physiology is study of how those organs function. Anatomy is is related to how they look their shape size... Physiology is how they work
Juveriya
anotomy dealt with the external and internal stuctural features of body and their constituent physiology deals with the functioning or action of that stucture
Tanveer
Anatomy is the study of the structures (internal and external) of a living organism. Physiology is the study of how the structures of a living organism function often at a molecular and cellular level.
Carmelo
anatomy is the structure of different body parts of human body and physiology is the normal body function of body parts of the human body
Akshay
anatomy is study of structure of the body e.g, system,organ's size shape location and physiology is the study of function of the body eg,eye ball movement , release of hormones , circulation of blood etc
Soumya
thanks
Tammy
thanks guys. I appreciate
Collins
thanks bro
SAGAR
Explain the meaning of life in a scientific manner
Dezni
probably it doesn't have a meaning yet it can be realised by certain signs that have a scientifically defined terms?!!!!
Osama
At least in a scientific manner, scientists have agreed that production and use of cellular energy, as well as growth and reproduction are essential when defining what is alive in a biological sense. For example, viruses are not considered alive because they cannot grow or reproduce by themselves.
Carmelo
this virus issues is being challenged currently.
Osama
what z your conclusion over virus bro?
Liyungu
pipo what is the relationship between T- cells ( specifically T-helper), & all three line of defence mechanism
Liyungu
anatomy is the science that deals with the study of the human structure whilst physiology is a science that covers the function and process of the body structure.
Vida
defien brache of Anatomy
Hamad
anatomy is the study of internal and external body parts while physiology is the science that covers the function and process of the body structure.
Priscillah

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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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