Questions tagged [immunology]

The study of the immune system in organisms, primarily responsible for fighting infection.

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To build up immunity, presentation of antigen by APC has to be complemented by presentation by normal cells?

Often immunization as a complex process is explained by: cells of the body taking up antigen and presenting them to cells of the immune system. In casual language there is no differentiation between ...
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Why is peanut allergy often more dangerous then other allergies?

From reading public media I have the impression that while peanut allergy is not more common then pollen allergies, peanut allergy is often more problematic and sometimes even deadly. Is peanut ...
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What does vaccine efficacy mean?

In the last few weeks, Pfizer/BionTech, Moderna and AstraZeneca have each released preliminary estimates of the efficacy of their SARS-COV-2 vaccines. But what do their respective efficacy percentages ...
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How does HIV know to attack specific immune system cells?

I'm no biologist, but curious of the answer to which I could not find online. How are Human Immunodeficiency viruses able to detect and distinguish immune system cells with a CD4 receptor on the ...
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SARS-COV-2 detectability versus viability

This week (#47 of 2020) two meta-reviews were published in the Lancet. Ct values and infectivity of SARS-CoV-2 on surfaces, a brief review published on 19 November in The Lancet Infectious Diseases, ...
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Do mRNA vaccines cause transfected cells to be killed by cytotoxic T cells?

Based on my research on how mRNA vaccines (specifically for COVID-19) work: An mRNA sequence, that contains the sequence of the coronavirus spike protein, is absorbed by some cells. These cells now ...
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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 ...
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Do antigen presenting cells present only antigens they have receptors for?

Having gone through and read Kuby, Janeway, Roitt on immunology, my understanding is that not each and every antigen of a virus will find its way to the MHCI complex on the cell membrane of antigen ...
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Can vaccination be explained by a principle of “broad specifity” of immune cells?

In the context of Covid-19, in Denmark all ferrets/minks in farms were killed, as there is infection in humans by the ferret corona-subtype. Counterintuitively, a virus transferred from ferret might ...
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Can a non-response to a vaccine be tested?

The BioNTech/Pfizer vaccine against SARS-CoV-2 is said to be 90% effective. Is there a test to establish the (degree of) success in individuals of a vaccine at provoking the desired immune response? ...
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Why is the SARS-CoV-2 target receptor ACE2 not endocytosed when bound physiologically?

The COVID-19 coronavirus SARS-CoV-2 enters cells by receptor-mediated endocytosis. See, e.g. here. Why doesn’t the enzyme ACE2 — SARS-CoV-2’s target receptor — undergo endocytosis when bound by its ...
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Is there such a thing as subclinical immunity?

This current CNN article suggests exposure to very low doses of a virus may be protective. However, I recall reading a flu study that found protective antibodies were only produced in symptomatic ...
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Destroying RNA of viruses using Ribonuclease

I wonder if it is possible to design some Ribonuclease to destroy only specific RNAs (like those of viruses). Then, if virus tries to infect, his RNA will be cut. Or, instead of creating Ribonuclease, ...
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Fate of antigen-presenting cells after antigen presentation to Helper T cells

In many texts, the Antigen-presenting cells (APCs) that initiate helper T cell responses are often "forgotten" after their antigen presentation function is discussed. I have been wondering ...
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How do Helper T cells activate Cytotoxic T cells?

Helper T cells activate the Antigen-presenting Cells (APCs) through their secretions (the cytokines) (although the T cell in question gets activated in turn). This is typically achieved by cell-to-...
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How to eliminate a prozone reaction or hook effect

I was doing revision for my test and came to a question that asks how to eliminate a prozone reaction or hook effect. I think done through refrigeration but one of my friend says it by diluting the ...
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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?
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Why can human viruses that can't infect chickens be grown in embryonic chicken cells?

Embryonic chicken cells are commonly used in vaccine production. The viruses are grown in chicken eggs, or in embryonic cells taken from those eggs, and then inactivated or attenuated to produce the ...
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Does germinal centre interaction with environment contributes by any means to the heterogeneity of the SHM-resulted antibody repertoire?

B-cells undergo a process of rapid mutagenesis and division which is followed by selection. Somatic hypermutation (SHM) produces many different antibody (Ab) genes that can potentially be useful ...
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What is a function-triggering antibody?

I am reading a journal paper on the effect of a neural cell adhesion molecule on neuronal development and in the abstract of this paper I have come across the following: The autophosphorylation and ...
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Can any molecule become a hapten?

Hapten are small-molecules, that can only become immunogenic when conjugated with a carrier protein. I was wondering if all small-molecules can become haptens (eg. by synthetic conjugation). Given ...
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At what age are mice considered too old for their thymus to stop being functional and produce T cells?

I am studying the effects of radiation on the immune system of mice. After exposing them to radiation, we will be harvesting their spleen, lymph nodes and blood to investigate immune cells such as T ...
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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 ...
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Auto-immune problems if immature B-cells released if bone marrow bone is fractured?

A fracture of a bone containing bone marrow with B-cells not yet taught to not recognize self-antigen, if the bone is fractured, can those cells get released and cause problems?
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What specific markers does a Covid-19 PCR test look for?

I've done a search and can't find anything as to what specifically makes a Covid-19 positive that identifies it as unique. I would expect to see something like this: https://madridge.org/journals-...
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Clonal selection theory, how does antigen reach lymphocytes? [closed]

Clonal selection hypothesis often defined by four basic principles of which first two are Each lymphocyte bears a single type of receptor with a unique specificity. Interaction between a foreign ...
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Help in understanding a sentence about TCR-MHC interaction and immune synapse formation

T-cell co-stimulatory and co-inhibitory molecules (collectively named co-signaling molecules) play a crucial role in regulating T-cell activation, subset differentiation, effector function and ...
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Can you still contract a disease after being vaccinated and be able to spread it?

I assume I know the answer to this already but wanted to confirm before I respond to someone that appears to be arguing that vaccines don't make you immune (they only stop your symptoms?) - but you ...
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What kind of people are more likely to catch COVID-19?

It is well known that people of old age or with respiratory problems are more vulnerable by the effects of COVID-19. However, I wasn't able to find information on any similar trends on catching the ...
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Why is it difficult for germs to jump species?

If you haven't watched CGP Grey's video Americapox: The Missing Plague, I suggest you watch it. It's an excellent video. One assertion he makes is that "germs jumping species is extraordinarily ...
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What is the mechanism responsible for long-lasting detectable antibody titers?

As I understand, when naive B cell encounters antigen matching its receptors and is activated by a T helper cell, it can either differentiate into 4 plasma cells, produce a lot of antibodies and ...
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When can we know if one develops immunity (to SARS-CoV-2)?

I've been thinking for this for a while. It seems there's no ethical experiment to perform to check if immunity is actually developed (the obvious experiment would be to expose someone that have ...
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Easy and cheap antigen/antibody couple

For an application I need to find a cheap antigen and cheap correspondent antibody. The antigen can be literally any molecule that is cheap and potentially easy to produce and with a correspondent ...
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Why is sheep erythrocyte lysis considered as classical complement activation pathway, and rabbit as alternative one?

Any suggestions are highly appreciated.
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How can I detect which antibody is produced by the B cell?

In the primary immune response, IgM is produced (in addition to IgD ). In the secondary immune response, various types of antibodies are produced. So how do I detect which antibody a B cell is ...
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Could there be a pathogen which does not activate an immune response?

In order for the immune system to be stimulated to produce antibodies, there must be a surface protein of the invading pathogen which binds to a receptor on B cell surface somewhat loosely. We need ...
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Cell-autonomous viral defense involving oxidative burst?

I'm looking for a mechanism by which a cell detects a virus (probably a retrovirus) within itself, then triggers an oxidative burst in response. This should all happen within the cell itself, ...
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How do animals contain and dispose of bacterial endotoxins (lipopolysaccharides)?

Gram negative bacteria naturally release endotoxins which are lipopolysaccharide molecules. These molecules are toxic to many eukaryote cells, including macrophages. My question is how animal ...
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Why is there no herd immunity against common cold coronaviruses?

In discussions of herd immunity against SARS-CoV-2 the underlying assumption usually appears to be that the virus basically stops spreading once a sufficient percentage of the population has overcome ...
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Do person with strong immune system have less chance of surviving SARS-COV-2 attack?

In most of the cases dealing with SARS-COV-2 disease, the major mortality cause is due to cytokine storm in response to Corona-virus that also attack healthy organs causing multiple organ failure. ...
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Examining antibody - target interactions in PyMOL

I'm a student currently looking at antibody responses against a viral target protein of interest. I have my own, annotated PyMOL session of my protein and I also have .pdbs of crystallised antibody ...
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Can intracellular protein initiate strong immune response?

Some autoantibodies escape immune tolerance and can cause autoimmune disease. In order to cause harm to the tissues by these autoantibodies, do the antigen need to be extracellular or membrane bound, ...
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Can the innate immune system defeat a pathogen by itself? Fast enough that we don't develop antibodies, etc.?

Would we have any way of knowing if our innate immune system destroyed a pathogen without involving the adaptive? Could a symptomless person who tests positive for COVID-19 with the RNA test, e.g., ...
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Why are antibodies Y-shaped?

I generally know how antibodies work by binding to antigens, but what is the specific purpose to being Y-shaped, as opposed to any other shape? Does this aid their function? Thank you.
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How is minimum infectious dose defined?

I'm a bit confused by the concept of a minimum infectious dose (MID). It seems from what my research so far has turned up, that while any dose greater than 0 could potentially cause an infection, for ...
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Why do viruses cause different symptoms?

If the sole purpose of a virus is to hijack the nucleus of a cell to replicate, why do we have different symptoms for different viruses? I can think of the following comming into play: immune ...
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What is the protein composition of complete Freund's adjuvant?

The complete form of this adjuvant uses heat inactivated and dried mycobacteria. However, to rule out cross-reactivity with an antibody, I would like to know which proteins are left in the adjuvant. ...
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How do PARPs counteract coronaviruses?

I read that [SARS-CoV-2 has] a nonstructural protein called NSP3, a component of which blocks the host’s efforts to fight off the virus. In particular, this protein shuts down host enzymes called ...
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Is it still true that C. elegans has no known natural viruses?

I read in a 2009 review that While mammals and C. elegans each have a single Dicer that makes both miRNAs and siRNAs, Drosophila has two Dicers: Dcr-1 makes miRNAs, whereas Dcr-2 is specialized for ...
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Reasons why this protein is not suitable as an immunogen?

In a paper entitled "Progress and Prospects on Vaccine Development against SARS-CoV-2", the authors write the following in section 2.5: "Compared with S, N, and M protein, E protein is not suitable ...

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