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Currently, pathogens "use" certain resources in a host, and then the host's immune system creates antibodies that eventually kill the pathogens (or the pathogen kills the host).

This is a pretty good understanding. However, antibodies are only one tool in the immune systems of complex animals. There are also a number of specialized immune cells that perform jobs like patrolling the body to try to detect foreign cells and objects to "label" as invaders, or phagocytes that try to envelope and digest foreign cells and objects. Additionally, there are strategies like making the body a less hospitable environment by increasing the temperature (fever). Antimicrobial chemical production is also very common in single-celled organisms but identified in fewer complex animals.

My question is: mirror or otherwise, could a pathogen "hijack" something other than usual as a resource?

Let's say, I don't know, Prime Pathogen A normally uses Prime Protein A, Mirror Pathogen A would require Mirror Pathogen A. Is it possible for a host to have a Prime Protein B that meets Mirror Pathogen A's requirement–perhaps not perfectly, but "good enough" to sustain Mirror Pathogen A?

Possible but, when looking specifically at the hypothetical "mirror" biology, less likely and probably would require specialized adaptations. The main problem that they would need to overcome, which is rather uncommon in known life is the mirrored shape of important biological molecules. Specifically, amino acids and sugars.

Both of these types molecules have a property known as "chirality", where the atoms in the molecule can be oriented in two ways, while still all being bonded to the same neighbors. These are known as enantiomers and designated with the prefixes "levo" ("l-"), meaning left, and "dextro" ("d-"), meaning right. Biology as we know it is very specialized to make use of l-amino acids and d-sugars. There are some exceptions but they tend to be rather specialized and less energetically favorable.

Some organisms can break down d-amino acids and use their atoms as nitrogen sources to build new l-amino acids. It is much, much more common, however, to use l-amino acids from either the host cells or their proteins. This takes the pathogen far less energy to accomplish as well as not requiring evolving specialized enzymes that most organisms don't have.

So, in the case of the mirror pathogen, it would have to have the ability and dedicate the energy to breakdown l-amino acids to build its d-amino acids. This would, indeed, likely result in slower growth rate. That, in itself, has a lot of potential to limit pathogenicity as high growth rate is generally required to be problematic. Phagocytes will still try to envelope and remove foreign objects that they don't "think" are alive, so, the mirror pathogen could face risk of excretion if it is not able to reproduce quickly enough to maintain a population.

So, overall, yes, hypothetically possible and even plausible (if the mirror organisms are able to metabolize d-sugars and l-amino acids) but less likely. Pathogenicity requires the ability to grow a population fast enough or otherwise evade the immune system which is also able act on "invaders" that it does not recognize as biological (maybe being really good at building a bioplaque that makes it difficult to move or use of toxins). Simply having mirrored chemistry alone is probably insufficient to evade the immune system enough to be pathogenic.

Nobel Laureates have never made ridiculous statements that didn't mesh well with scientific evidence. Kary Mullis, Nobel Laureate in Chemistry, credited with discovering PCR would never be quoted as refuting the evidence of HIV as causative in AIDS, cited in a journal article questioning the evidence, and then the journal article retracted due to it being inaccurately labeled as "Hypothesis and Theory" instead of opinion, factually inaccurate, and dangerous - oh. Oh no:

https://pmc.ncbi.nlm.nih.gov/articles/PMC6830318/

Next thing, you'll tell me that scientists are humans that are fallible and some of them sometimes engage in ethically-questionable activities and sensationalism for profit.

https://www.scribbr.com/fallacies/appeal-to-authority-fallacy/

FYI: Just because someone is a Nobel Laureate does not mean they are correct.

I dont think i have given them any credit. I would argue i simply didn't dispute them out of hand. Especially as you did without backing myself up with evidence of my own credentials.

I also thought i expressed that we should all be sceptical of anything we read on the internet. My issue was how you weighted your sceptisism. You seem to have automatically given all credibility to a reporter, under the assumption that they held no bias that affected the story they wrote.

For all you know, the random poster on the internet may be a legitimate scientist and expert who disagrees with them. Their opinion may be just as valid as the opinion in the report.

As a recent example, google released a quantum computer chip, and lemmy immediately ripped apart the reports and media buzz around what it was actually capable of. I believe that this is a great example of healthy sceptisism.

I believe that what you did is an example of unhealthy or misplaced sceptisism.

Granted, if it turned out that this random poster was absolutely unqualified to make the assertions that they did then absolutely you would be in the right.

I just dont think its helpful to dispute them out of hand with nothing to back you up.

This is actually a fair and good question to ask. Being too credulous of things read on the Internet has shown rather problematic in recent years. Taking everything written in academic journals, especially opinion pieces not based upon peer-reviewed evidence, without skepticism has shown to be problematic since before the Internet, however.

I'm kind of surprised by the reaction you're getting here as I had the same exact question (you can see that I posted it before seeing yours).

Knowing that the person has some background in biology helps, but that was not clear in the initial comment. And even still, I lean toward believing the actual professionals who have studied this exact thing for years over some random person on an internet forum.