Bacteria, viruses, antibodies, and other?

! - Bacteria are large, single cell, killed by antibiotics. Viruses are small, more like the size of a cell nucleus, with few drugs that effect them.


2 - We develop antibodies against both is that right? Once an antibody is developed against a virus, we would be set for life, until a slightly different strain. this is why we have fewer colds as we get older. But that is not true in the case of bacteria is it?


3 - If a single instance of a bacteria or virus getting into our blood could infect us, it seems to me we could never avoid such. There must be more to it, a minimal number of "jerms", or something. I'm confused about that.


4 - We have other defenses, in what sort of cases do they get the job done without antibodies.?


Thanks

Bacteria, viruses, antibodies, and other?
In response to





1.) Bacteria are LARGER than viruses; in all its terms, they are not large, but relatively larger to viruses (protozoans are LARGER in some respects to bacteria, so this defeats the definition of bacteria being large organisms). Antibiotics are but one kind of medication, i.e. there are a lot of them, but the same one--antibiotic; viruses are not cellular organisms, so the drugs directed to them are different from those used for bacteria.





2.) Actually, we would not necessarily be "set for life" as the titer of antibodies in our system can only last until the next re-challenge, which is the anamnestic response stage; this is like getting vaccinated, in that vaccination induces the production of antibodies, but you still need to get the booster shot after some number of years depending on the vaccine because they are not meant for lifetime protection (in general terms, your immune system "knows" a pathogen, but forgets it after some time because it does not constantly "remember" the pathogen). This standard is the same for ALL pathogens, whether they are viral, bacterial, fungal, or parasitic in nature.





3.) Yes, there is a minimum number of colonies (for bacteria) and viruses that invade our bodies in order to cause a systemic disease--of course, the number depends on the pathogen, as some need more before establishing an infection, while some need only one aggressive cell to initiate the disease itself.





4.) Well, you are living with one right now--your skin! It is the outermost, main barrier against pathogens, and it is an excellent barrier IF INTACT, since breaks in the skin such as abrasions can initiate penetration of pathogens in the skin. Phagocytic cells, like macrophages, need not have antibodies to initiate phagocytosis because they just eat anything that is non-self or degraded (of course, antibodies activate them further). Mucus secretions in our epithelial lining of tissues "stick" pathogens instead of them getting into areas where they can cause infection. Our body temperature as well can serve as a defense as some organisms cannot tolerate body temperature (that is why we get fever, because it is a defense mechanism, and this is also why Treponema pallidum, the etiologic agent of syphillis, can only live in the less warm areas of our body such as the urethral lining).





Hope this helps!
Reply:When we become ill, our white cells increase to fight the bacteria or virus. That is also a way a doctor that call if you have an infection, by taking a Complete Blood Count, or CBC. I hope this helps you somewhat. If our white cells are under 10, we will probably be able to fight the virus or bacteria.





Anyway, it sounds like you know a lot about both and you gave more information than questions so I hope I picked the right one. Thanks.

camellia