Behind the scenes: Maria Daly and the flow cytometry facility

Maria Daly is manager of the LMB’s Flow Cytometry Facility, which provides LMB scientists with state-of-the-art instrumentation to characterise, quantify and separate particles on the basis of multiple parameters, such as size, surface and intracellular markers, DNA content and fluorescence intensity. Maria joined the LMB in 2009, having worked in several key laboratories including in Dublin, London and Miami, and has seen the LMB facility grow and diversify over this time.

Here, Maria recalls her history and career with flow cytometry and how coming to the LMB completed her career circle.

Early days in flow cytometry

My first encounter with a flow cytometer was in 1981, in my very first permanent job, at Technicon in Dublin. We flowed cells past a tungsten filament lamp, then measured the scatter characteristics of each cell. We could also measure absorbance of certain dyes and deducted from that five-part differential white cell counts, red cell counts and platelets. But it wasn’t the formal flow cytometry as we know it today: it was a haematology analyser. This gave me the experience to apply for a job as a flow cytometrist at the Royal Postgraduate Medical School (RPMS) in London, where I then got properly trained on flow cytometry. Just like flow cytometry, my career flowed along, and I had the opportunity to work at GlaxoSmithKline, the Diabetes Research Institute in Miami, and Oxford Immunotec, before arriving at LMB as the Flow Cytometry Facility Manager. My past sort of met my future when I came to the LMB, as I had previously worked with John Savill, Mark Walport and Leszek Borysiewicz at the RPMS, who were leading lights at the MRC.

LMB and the history of flow cytometry

I was especially excited to join the LMB and be involved in the same Division (Protein and Nucleic Acid Chemistry) as César Milstein, working alongside people who knew him. He is the father of monoclonal antibody production. One of the key names in flow cytometry and its development, its early design and evolution was Len Herzenberg, who actually came to the LMB in a short sabbatical (1976-77) to work with César. Following this visit, Herzenberg developed fluorescently-labelled monoclonal antibody reagents to identify and sort functional cell subsets: up until then that wasn’t being done. We could label things like DNA with dyes, or you could label cells with a particular dye, but this was a way of sorting cells into many subsets. So, it’s amazing to be in a place where all that originated and came together. I could see, through my years with flow cytometry, how monoclonal antibodies and all that developed into research, and then into the clinics for leukemia, immunophenotyping and so on. That’s a cornerstone now in immunology labs and clinical labs.

Creative growth of flow cytometry

When I first arrived at the LMB I thought I was being constantly tested, because people were coming into the lab saying, ‘Maria can you do this with flow…can you do that?’ I thought they were trying me out to see if I could do the job. But that’s not true. I think that the people here are very inventive and creative. They have lots of applications and if they can find a way to do something, that’s what drives them. So, I have had requests for so many different applications, and that’s what I really like about the LMB – it keeps you interested, keeps you on your toes and keeps challenging you. Also, LMB people chat to each other and exchange ideas, especially at the Lab talks every October: that’s a big melting pot of ideas. From that, we’ve cross-pollinated different groups and the flow cytometry unit has really grown. In my first year, I was on my own and worked mostly with PNAC – I think we had about 55 people who used the facility. There are now three of us in the team and last year we climbed to 149 people using us across 36+ groups, and now they’re from all the LMB Divisions and the University Wing. The best part of my job is the people that I work with, the fun of working with some of these people to get a technique working, to get successful results – I love that!

I’ve also been lucky to get involved with some work where the groups have actually put me as an author on their paper, because flow cytometry was quite key to the development of that work. The first one, a Nature paper, was back in 2010 with See Heng Wong in Andrew McKenzie’s lab. They discovered a cell type called innate lymphoid cell type 2 and I felt really privileged to be a part of that discovery. It’s been nice to be involved with the groups like that.

The LMB also makes you feel involved in other breakthroughs through events such as the Nobel Laureate parties, which came as a real surprise to me. I went to one just a few months after I started. Someone popped their head around the door and said to me, ‘Maria, you get cake in the canteen!’ It was so exciting. It’s something I did not expect when I came here, and now I’ve been to three in the last ten years.

Obviously, this year we have had to make changes in how we operate because of COVID regulations. Normally the door is always swinging open and closed, but not so much this year. Usually we have four sorters and six analysers, but in these socially distanced times some of those analysers are remote and in different rooms, and we can only use two sorters at a time. The biggest challenge we’ve faced is in training people to use our analysers. At the moment that’s a mixture of Zoom calls to do the theory, and distanced practical sessions. However, the Zoom calls have also been a positive to come out of this, as it’s much easier to arrange for people to be together remotely at any one time, and we can discuss upcoming experiments. But that brings us its drawbacks as well – people can’t just pop in and ask you a quick question, and I miss that.

Looking to the Future

The field of flow cytometry is evolving all the time, and I feel lucky that I was in it from the early days – when we were just using a couple of colours (dyes). Now people coming into the field are overwhelmed because we have so many parameters. The optics, the electronics, everything’s developed, everything’s miniaturised, everything’s built on – so we have a greater number of colours we can combine together. While traditionally we look at flow cytometry as bands of light, now people are starting to look at spectral cytometry which requires deconvolution running at 20,000 events per second to un-mix those spectra. Just this year, in May, a spectral sorter was produced which is capable of running tens of thousands of events/second and un-mixing the spectra. So, it looks like instead of us looking at bands of light, the future now for flow cytometry is looking at spectra.

Similarly, the wider community of flow cytometrists is also expanding. When I first came to Cambridge, there were just six facility managers – we used to meet in the Wok ‘n’ Grill in Trumpington and just chat. Now it’s grown so there’s more than 30 of us – it’s getting more and more difficult to find a venue! Interacting and networking with other flow cytometrists – whether it’s the local Mid-Anglia Cytometry [MACC] Club, or the national and international meetings – is an aspect of my job that I really enjoy. It’s lovely when you belong to a wider community, as we can all exchange ideas or help troubleshoot any problems with our equipment. I’m looking forward to the time when we can meet in person again.

Maria was interviewed for the 2020 Alumni Newsletter on the 30th of November.