An English interview with a short presentation about your experience. The department studies why people's immune systems respond so differently, using lab data at very large scale. Your mix of wet-lab work and Python is the core of your pitch.
Monday09.11.10:15
Monday 10:15 German time
Format
Zoom, in English, about 20 minutes, with your presentation (max. 10 slides)
Panel
Dr. Bibiana Costa (Scientific Project Manager, BiiM) and Mrs. Han (PhD student)
Status
On 5 Nov you asked to move it because of a dentist appointment, and said you would come on Monday if they can't move it. No answer yet. Replies come by Gmail via SuccessFactors.
Zoom link
Not in the invitation. Ask for it when they confirm the time.
CiiM (Centre for Individualised Infection Medicine) is a joint centre of the Helmholtz Centre for Infection Research (HZI) and Hannover Medical School (MHH). Its new building in Hannover was due to open in 2026.
BiiM is the Department of Computational Biology for Individualised Infection Medicine. It is led by Prof. Yang Li, who is also CiiM's director.
Research: why immune responses differ between people, to predict who is at risk from an infection. They combine genetics, single-cell data and immune measurements from large groups of people.
Known result: a “single-cell immune aging clock” (Nature Aging, 2025), built from more than two million immune cells from blood samples of about 1,000 healthy people aged 18 to 97.
I couldn't find the job ad online. The likely tasks are an educated guess for a lab in this kind of department: processing human blood samples (PBMC isolation, counting, freezing), stimulation assays and cytokine measurements, DNA/RNA isolation and QC, preparing samples for single-cell sequencing, and keeping the sample database. Compare this with the ad you applied to.
Your angle: a computational department needs lab people who understand what the data is used for. You run assays carefully and you analyze data in Python. Say that early and say it clearly.
Max. 10 slides · aim for 8–9 minutes
Slide plan
About 50 seconds per slide. One message per slide, few words, one picture or graph where you can. Save a PDF copy in case screen sharing fails.
My path. Studienkolleg (FH Aachen) → B.Sc. Bioengineering, Hochschule Rhein-Waal (taught in English) → 13 months in the lab at University Medicine Essen. English C1, German C1, Persian native.
Where I worked. Thoracic oncology research lab at the Ruhrlandklinik, University Medicine Essen. Patient-derived mesothelioma cell lines. Supervisor: Dr. Balazs Hegedüs.
Cell culture. Sterile mammalian culture, passaging, cryopreservation, counting with the NucleoCounter NC-3000, drug treatments on a schedule.
Assays. SRB viability assays, dose-response curves and IC50, combination treatments, at least three biological replicates.
Protein and flow cytometry. Western blot (TROP2, TFEB, β-catenin, β-actin loading control). Surface staining with unstained and isotype controls, % positive and MFI.
Thesis in one slide. Question: does blocking autophagy change TROP2 on the cell surface? Six cell lines, three drugs. Surface TROP2 ranged from 44% to 1% positive cells. Show one histogram.
A data-quality decision. Nintedanib glowed on its own, so its flow data looked like staining. I recognized the artifact using the controls and left those samples out instead of reporting false values.
Data analysis. Python (pandas, NumPy, Matplotlib). MesoLab Analytics: dose-response fits with confidence intervals, built for the group. Co-author of a paper in Cells (2025).
What I bring to CiiM. Careful sample handling and documentation, plus an understanding of the data that comes out. Eager to learn PBMC and single-cell workflows. Thank you.
Don't over-claim: on slide 9, say “co-author”. On slide 8, keep it to what happened: you excluded the data, and the thesis names it as a limitation.
Prepare these; tap to open
Questions they will probably ask
Why do you want to work at CiiM?
I want my lab work to feed directly into research that uses the data. At CiiM, every sample becomes part of a large dataset, so careful handling really matters. I also like that I can understand and support the analysis side, because I work with Python myself.
Have you worked with human samples, like blood?
Not with fresh blood yet. I worked with patient-derived cell lines under sterile conditions. I know the principle of PBMC isolation by density gradient and the safety basics for human material, and I'm confident I can learn the routine quickly with proper training.
How do you keep track of many samples?
I label everything clearly before I start, keep a sample sheet that matches the tube labels, and double-check IDs at every transfer step. I record what I did right away, not at the end of the day. I prefer a database or LIMS over loose notes, because errors in sample IDs ruin the data later.
Tell us about a problem in the lab and how you solved it.
In my thesis, Nintedanib-treated cells looked positive in flow cytometry. Comparing them with the unstained and isotype controls, and with the literature, showed the drug itself was fluorescent. So I excluded those samples and named it as a limitation, instead of reporting a false increase.
How do you work with the computational team?
I think I can be a good bridge. I understand what clean metadata and consistent formats mean for analysis, because I wrote my own analysis tool. I'd make sure every sample comes with complete information, and I'd ask early when something in the protocol might affect the data.
When can you start? Would you move to Hannover?
Decide this before Monday. A clear answer helps: “Yes, I would move to Hannover, and I can start [date].” If they ask about your Political Science studies in Münster, have one honest sentence ready.
Read once before Monday
Refresher
PBMC isolation
Blood diluted and layered on Ficoll, then centrifuged without the brake.
Red cells and granulocytes go to the bottom. PBMCs (lymphocytes and monocytes) collect in the white ring between the layers.
Washed, counted, and frozen in medium with DMSO.
Stimulation and cytokines
Cells are stimulated, e.g. with LPS or pathogens, to see how they respond.
Cytokines such as IL-6, TNF-α and IL-1β are measured, often by ELISA or bead assays.
People differ a lot in these responses, which is what BiiM studies.
Single-cell sequencing
Each cell goes into a droplet with a barcode, so every RNA read can be traced back to its cell.
Gives the cell types and their activity in one sample.
Needs fresh, viable cells with little debris, so sample handling matters.
eQTL
A genetic variant that changes how strongly a gene is expressed.
Linking genotype to expression and immune responses explains part of why people differ.
Ask 2–3 at the end
Your questions for them
What does a typical week look like for the technical assistant?
Which samples and cohorts would I work with, and how many samples per week?
How do the lab and the computational team work together day to day?
Would I be trained on single-cell sample preparation?
What are the next steps, and how long is the contract?