Anthony writes:

Mice Infected with Low-Virulence Strains of Toxoplasma gondii Lose Their Innate Aversion to Cat Urine, Even after Extensive Parasite Clearance

This paper was covered on TWiP 60.

To split hairs, the infection in mice does not remove the fear of cats.  It removes the hard-wired aversion to cat urine.  


Steve writes:

Hi Vincent, Cindy & Steph,

Thank you all for what is sounding like a well honed team effort on ‘Immune’ already, which I’m sure is going to give TWiP a run for its money as my most eagerly awaited podcast from the stable! (y)

Only once a month, for such a many-sided subject seems like it’s going to take a long time to build an overall picture of the components and functions of the system though. So I wondered if you could do something to bring together the Audiommunity collection with the new Immune archive, so that new listeners can easily go back and pick up some of the subjects already covered–such as MHC/grafts, T-cells, B-cells/germinal centres.

The Audiommunity podcast followed a bit of a random pattern, but, it would, nevertheless, enable picking up more background on the subject between Immune instalments.‎ You do include some of the podcasts in your guests listings, but the earlier episodes are missing, and the order is a bit confusing. (Even on their own site, they just list dates for the early ones, with no indication of what they cover until the links are opened–yet some are very good.)

I’m going back through them now, but I think I’ll need to go over them many times before the different  components begin to sink in and be properly remembered (I think I’ve had a book on ‘Complement’ in the ‘to read’ pile by my bed for about 30y! 🙂 ). It would also be easier if the initials were explained when first mentioned. I for example, knew what the ‘Major Histocompatability Complex’ was, because I was very impressed by a Scientific American article I read on it in the 70’s; and I knew that ‘CD’ meant ‘community of differentiation’, but I didn’t know that the ‘m’ of ‘IGm’ was for ‘membrane’, and had forgotten that ‘T’ in ‘T-cell’ was for ‘thymus’. These terms are generally just talked of by their abbreviations, but it’s hard to take in, if one can’t pin them down to a place or function by knowing what the names mean.‎   A programme giving an overview of the key pieces of the whole immunity jigsaw–and how they were discovered–would be appreciated.

Another thing that would be useful: I particularly like your coverage of the ‘current affairs’ affecting science–in all your podcasts–and I would like to be able to share them with friends and people who could help ‘the cause’, without having to post a link to a long programme and expect them not to be put off in finding the relevant part. This week’s discussion about the graduate students’ stipends, would be a good one to share widely, for example.  The running time points help, but it would be best if, as well as the audio or video of the whole programme, clips of the individual topic discussions could be included as well, so that they could be easily referenced and shared.  ( I would offer to copy and edit the individual pieces for you, but I’m long term sick and could not do it very reliably.)

Anyhow, it’s great that you’ve managed to come up with yet another podcast that’s a first choice when seeking something intelligent to ‘chill’ to; and all the more so for not being jammed with background music and noisy, unrelated, adverts, as happens with a lot of YT presentations by others.

Many thanks,


In Luton, Bedfordshire, England.

Where the weather is mostly grey lately, but with an occasional unexpected ‘hurricane that got lost’, and brown sky, with Sahara dust, and Portuguese forest fire smoke!

Peter writes:

Greetings Immune Team.

I am much enjoying the new podcast, a great addition to My own immune system has not well this autumn: I caught influenza before I had had my annual flu shot (the timing would suggest that I caught the virus on a flight or at an airport) and then developed secondary bacterial pneumonia, with pleurisy that required a few days in hospital. After a couple of months I am starting to feel better but still have a persistent nasal drip which my doctor has so far failed to find an effective treatment for.

Enough about me.

I have some immunology questions for the team.

If our cells are infected by viruses, are there any intracellular defences that can eliminate  the virus from the cells  or is just a matter of triggering apoptosis to try to kill the cell before viral replication, or if the virus blocks apoptosis pathways, sending cytokine signals to instruct NK cells to come and destroy the infected cell?

What happens with viruses that become latent? I presume that the immune stops virus replication but is unable to eliminate the virus from the cells, since viruses can break latency the blocking of viral replication is clearly an active process by the immune system.

On the subject of latent infections, in the UK the chickenpox vaccine is not on the vaccination schedule, but the NHS offers a free shingles vaccination (zostervax) at age 70, which I understand is the same as the chickenpox vaccine, but a higher dose. The higher dose being needed because it is intended for the elderly who have a poorer immune response.

It seems to me that having a single shot of varicella vaccine at a younger age would act as a booster helping to repopulate the immune system with the appropriate immune memory cells and thus maintain the zoster virus in a latent state.

Do you think that giving someone in their mid 50s a single varicella vaccination would boost immunity and have the same effect as Zostervax at seventy in preventing shingles?

Maybe this idea is rubbish, but I would welcome your opinions on this.