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Questions tagged [immune-system]

This tag is for general questions related directly or indirectly to the vertebrate immune system, but are not questions directly related to Immunology, the discipline of the study of the immune system.

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Why aren't all B cells memory B cells?

If we have a B cell for every possible type of antigen, why aren't all of them memory B cells? From my reading, I have deduced that memory B cells are effectively the better version of normal B cells, ...
Avkash Panwar's user avatar
1 vote
1 answer
3k views

Would the human body somehow get rid of very fine glass particle(s) that have penetrated the skin?

Assuming that a speck of glass dust has adhered to your finger and after a few days, you notice occasional discomfort when gliding your finger over surfaces (but non if you let the finger alone). It ...
iwab's user avatar
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Can thymocytes end up in a lymph node instead of thymus?

Can thymocytes exiting bone marrow end up in a lymph node instead of thymus? If not why? Here is my thought: thymocyte in the bloodstream, on its way to thymus, can leak into interstitium with blood ...
MCH's user avatar
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Can In Vivo Gene Therapy Cause allorecognition/Rejection?

Organ rejection from organ transplants is least common when donors and receivers are genetically related; As I understand it, this is because the antigens on the surface of the cells of the donated ...
Gnat's user avatar
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In atherosclerosis, why do apoptosed macrophages stay on the endothelium?

In atherosclerosis, the following process happens: Lipid deposits of LDL-cholesterol happen on the endothelium They triggers an inflammatory reaction of the endothelium: macrophages circulating in ...
totalMongot's user avatar
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13 views

What can lymphocyte-produced antibodies do that 'innate' opsonins can't?

I have a conceptual misunderstanding relating to immunology which I'd be grateful if anyone could help me clear up. My A Level textbook says that at the start of an immune response, opsonins bind to ...
user265902's user avatar
8 votes
0 answers
261 views

Why does the thymus gland shrink with age?

What exactly is reason/process/mechanism for which our thymus gland starts to shrink with age? The thymus gland is the site of production of T lymphocytes which are the best defence against infection ...
Kshitij Kumar's user avatar
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33 views

Are there autoimmune disorders caused or mediated only by T cells?

I have frequently read that 'most' or 'the vast majority' of autoimmune disorders involving the adaptive immune system are caused by autoantibodies. These comments imply that there are known disorders ...
Kurt Hikes's user avatar
2 votes
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42 views

Can macrophages phagocytose viruses directly?

I've been reading that Macrophages, members of the innate immune system, can actively track bacteria and protozoa to devour and destroy them. In the same way, can macrophages devour free viruses, in ...
Vembha's user avatar
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4 votes
0 answers
116 views

Why are lymph nodes located where they are? [closed]

According to the National Cancer Institute, a subdivision of the National Institutes of Health, clusters of lymph nodes are found in the neck, underarm, chest, abdomen, and groin. Why are lymph nodes ...
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What's the exact mechanism of oral tolerance? [closed]

I have mainly two matters of confusion need to be clarified. First question: The immune system does not necessarily kill everything hat has PAMPS, the bacteria living in the gut, have PAMPS (Pathogen-...
Tong Su's user avatar
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how do phagocytes receptors work now and in the past?

As we know, phagocytes have receptors on their cell that are used to detect pathogens which they bind to and engulf them. That seems easy. Though, I'm trying to wrap my head around the fact how the ...
Giorgi Lagidze's user avatar
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43 views

How does the body avoid making an immune response to self-antigens?

The body contains antigen-detecting and presenting cells (APCs) including leukocytes and cytokines each having their characteristic HLA genes consisting of different recognition sites that detect the ...
hali's user avatar
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1 answer
191 views

What are monocytes with vacoules called?

I've heard that monocytes sometimes appear with vacuoles. Do monocytes with a vacuole have a name? If so, do monocytes without a vacuole have a name as well?
Marcus Gorayeb's user avatar
4 votes
0 answers
29 views

Exhaustion of 'memory' CD8 T cells

I've been reading literature on the exhaustion of cytotoxic CD8 T cells. In many of the papers I read, the authors aim to delineate molecular mechanisms that differ between exhausted and memory ...
Vembha's user avatar
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1 answer
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CDRs and antigen-binding sites [duplicate]

Are complementarity determining regions (CDRs) not the same thing as antigen-binding sites? If not, what is the difference? An old exam question states: "Clarify how CDRs are related to the ...
user71502's user avatar
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1 answer
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Role of the CD3 proteins and ζ chain

Could someone please explain which of the following is correct and why? The role of the CD3 proteins and ζ chain on the surface of the cell is to: a) transduce signals to the interior of the T cell b)...
user71502's user avatar
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1 answer
738 views

What is the difference between a macrophage and dendritic cell?

I am aware that both these cells (monocytes) are phagocytes and are able to present antigens upon their own Class II - MHC integral proteins. Other than their difference in structure (size and shape), ...
Jamo's user avatar
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3 votes
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T-Cell Receptor Receptor-Associated Immune Receptor Activation Motifs (ITAMs) Inconsistency

In reading the information associated with the cytoplasmic machinery of the T-Cell Receptor (TCR), the one tyrosine motif that is consistently mentioned is the receptor-associated immune receptor ...
Hawkeye's user avatar
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1 answer
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Are individual auto-reactive 'lymphocytes' or auto-reactive 'clones' generated in the central lymphoid organs?

Clonal deletion is a well-known mechanism of immune central tolerance. But individual lymphocytes or lymphocyte clones are subjected to apoptosis? If clones, then what is the reason to allow mitosis ...
abc's user avatar
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45 views

Abilities used to survive against natural enemies: directional selection or frequency-dependent selection?

Regarding abilities used to survive predators and parasites, are they subjected more to directional selection or frequency-dependent selection? It's usually that host-parasite coevolution is ...
sterid's user avatar
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Antigen transfer from baby to mother

When considering immunity in babies, the main mechanism that supports their undeveloped immune system is the transfer of antibodies from mother to baby via breastfeeding. Case #1: both baby and mother ...
stanislav-iablokov's user avatar
1 vote
0 answers
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Why there is swelling when skin doesn't break visibly? [closed]

I had read that swelling occurs as result of blood vessels pouring watery fluid in the affected area to help in fighting the incoming pathogens, when we our skin is cut open. However sometimes like ...
Kshitij Kumar's user avatar
0 votes
0 answers
125 views

What is the optimal temperature for Omicron to thrive in?

I have always been under the impression that when sick, you should let a fever run its course. The accepted answer to the question Why do people take drugs to lower a fever? seems to provide some ...
user38770's user avatar
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2 votes
1 answer
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What is the significance of an adjuvant to traffic vaccine antigen directly to draining lymph nodes without diffusing into the systemic circulation?

I found the following sentence in the this paper- Safety and immunogenicity of an inactivated SARS-CoV-2 vaccine, BBV152: a double-blind, randomised, phase 1 trial An imidazoquinoline molecule, which ...
Prem's user avatar
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3 votes
1 answer
79 views

Is the response to a vaccine correlated with the reaction to the disease?

I was wondering if the response to a vaccine correlates with the reaction to the disease. For example, if someone had a strong reaction to a vaccine, this person would also have had a severe course of ...
ethuser55's user avatar
2 votes
0 answers
73 views

How much of TLR 7 agonist is safe for human beings, as it is both linked to development of autoimmune diseases but is also used as Vaccine adjuvant?

This question is motivated by the fact that TLR 7 agonists have been linked to development and acceleration of Lupus-like disease both in animals and human beings. But at the same time, TLR 7 agonist ...
Prem's user avatar
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27 votes
5 answers
5k views

Why did scientists state that the Omicron COVID-19 variant was a reason to get a booster?

I was watching Vox’s video, Big questions about the Covid booster shot, answered, which references the New York Times article Omicron Prompts Swift Reconsideration of Boosters Among Scientists. In ...
hb20007's user avatar
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1 vote
0 answers
21 views

What is the definiton of repertoire shift in B cells?

I am new to biology and trying to understand this term. Couldn't find a comprehensive defintion. Thank you
LOVEMATH's user avatar
1 vote
0 answers
52 views

What is the upper limit for 'active' vaccinations

As far as I know the effect of vaccines is caused mainly by creating Memory Cells specific to a single pathogen. As there is obviously a lower limit of memory cells needed for immunity ( at least one),...
loreson's user avatar
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5 votes
1 answer
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What animal has the strongest immune system?

I'm wondering what animal has the strongest immune system. It can be defined as the most evolved immune system or the immune system that can eliminate or tolerate most number of (different) viruses/...
ermanen's user avatar
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11 votes
2 answers
2k views

Viral vector vaccines - why doesn't the viral vector get attacked by the innate immune system?

I've been looking at how the Astrazeneca Covid-19 vaccine works: A chimpanzee adenovirus (the viral vector) is injected into the patient. After entering a cell, the viral DNA is deposited in the host ...
Naj's user avatar
  • 315
6 votes
1 answer
786 views

Why do the mRNA vaccines for COVID need special lipids?

I've read that the Pfizer mRNA vaccine is delivered to the cell by encapsulating the fragile mRNA into a lipid nanoparticle. However, the lipid has to be PEGylated in order to avoid immunogenecity. ...
Jake Evans's user avatar
5 votes
0 answers
70 views

Are autoantibodies against intracellular proteins "functional"?

Autoantibodies against intracellular proteins have been detected in some autoimmune diseases (For example, TRIM21 in Sjögren's syndrome and NALP5 in Autoimmune Polyendocrine Syndrome Type 1). My ...
Josuke's user avatar
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3 votes
0 answers
148 views

Do COVID-19 vaccines produce more spike protein than natural infection?

The SARS-CoV-2 spike protein has been shown to be harmful on its own. However, a news article quoted an "expert" as saying The spike protein components of the vaccine are not produced in ...
user avatar
7 votes
2 answers
450 views

Is the covid-19 vaccine-induced copy of the protein spike also damaging cells?

In recent scientific articles, it has been discovered how the spike protein not only is a respiratory disease but also damages blood vessels cells directly, and is connected with higher risk of ...
Cris's user avatar
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3 votes
0 answers
37 views

How do APCs find their specific T-cells in the lymph nodes?

My understanding is that when an APC (more specifically a dendritic cell) encounters an antigen in the periphery, it ingests it and presents it on its surface. It then migrates to lymph nodes to ...
Kareem Atef's user avatar
3 votes
1 answer
133 views

Is covid vaccine helpful for a covid patient?

I am not a biology student and this question came in my mind out of nowhere. I read somewhere that the vaccines contain some denatured or almost dead corona viruses and when these are injected in our ...
Ankit's user avatar
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1 vote
1 answer
103 views

Does stronger reaction to vaccine (fever, days of nausea) mean that an immune system would have reacted the same to the virus?

I have heard that the real danger of Covid-19 is the strong immune response. Is it more likely that a person's immune system would have reacted dangerously to the virus?
Mark K's user avatar
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0 votes
0 answers
22 views

What makes a bacterium move away from a neutrophil cell?

In this video we see a bacterium seemingly moving away from the neutrophil that is chasing it. What mechanism makes it "want" to avoid the neutrophil? It doesn't seem to mind being around ...
Retardi Grade's user avatar
1 vote
0 answers
167 views

What differentiates bound antibodies from unbound ones?

When an antibody is bound to an antigen, it can then stimulate a FcR receptor on a phagocyte etc. to respond to the threat. What stops 'free' antibodies from spuriously activating an immune response? ...
Reinstate Monica's user avatar
3 votes
1 answer
59 views

Why is graft-vs-host so selective against phylogenetically close cells?

Is there a well established explanation for the phenomena that graft-vs-host is so much more selective against phylogenetically close cells? See historically significant references below, "This ...
50cent's user avatar
  • 49
0 votes
1 answer
31 views

Which landmark paper first described the differentiation of T-cells?

T-cells are distinguished from B cells in part by their locus of differentiation/maturation (thymus). This is textbook knowledge, but I was wondering which particular person or people were responsible ...
alghazali's user avatar
1 vote
0 answers
20 views

How does lactate produced in the intestines get transported to the rest of the body?

Some gut bacteria known as lactic acid bacteria(LAB) are known to produce lactate in the intestines and they confer beneficial effects such as enhancement of the immune system, but I assume not all of ...
jojo's user avatar
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2 votes
1 answer
64 views

What happens if a circulating naive B cell is met with a polysaccharide/lipid antigen?

These antigens should provoke a T-independent response, so will they differentiate then and there to form short-lived plasma cells? Or do they have to go to lymphoid tissue, enter a B follicle, and ...
Jaja bae's user avatar
  • 139
10 votes
1 answer
490 views

Spike protein production by mRNA vaccines?

I am trying to understand the spike protein production mechanism of the mRNA vaccines, and during my research I learned that the mRNA (Moderna, mRNA-1273) vaccines hijack the cell machinery to produce ...
albin's user avatar
  • 201
1 vote
1 answer
54 views

Why can't C1r cleave C4 proteins?

I am researching the complement system, and have ran into something I'm not really sure about. In the past, the C1r2s2 complex was thought to be an 8-like structure tucked inside C1q's collagenous ...
chematwork's user avatar
1 vote
0 answers
54 views

How do injected purified anti-D antibodies prevent the natural production of antibodies in order to prevent Hemolytic Disease of the Newborn?

Treatments involving Anti-D antibodies are given to pregnant women carrying Rh+ fetuses when the mother has an Rh- blood type in order to prevent Hemolytic Disease of the Newborn during the 2nd ...
JulianS's user avatar
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-1 votes
1 answer
81 views

Why is the food we consume right from birth not immunogenic to elicit an immune response? [closed]

Excluding the hypersensitive reactions which are individual specific, how is food we consume considered safe by the immune system?
Sucharita Chatterjee's user avatar
0 votes
0 answers
16 views

Howthe body differentiate between foreign and native protein? How does it know when to create an immune response? [duplicate]

How the body differentiate between a foreign and a native protein? Suppose there is a bacteria, it has lot's protein on its membrane, with specific structures. How does our body know it's the foreign ...
Aditya Shrivastava's user avatar