The cell line has just recently been genetically characterized. I did not find the karyotype on github but I would suggest to get in touch with the project contributors.
The ploidy of the HT22 cell line, derived from mouse hippocampal neurons, is not widely reported in the literature. It is possible that the specific ploidy information for HT22 cells has not been extensively characterized or published.
The ploidy of a cell line refers to the number of sets of chromosomes it possesses. Most commonly, cell lines are characterized as either diploid (containing two sets of chromosomes) or aneuploid (having an abnormal number of chromosomes). However, to determine the precise ploidy of a specific cell line, further investigation and experimental analysis would be required.
If you need to determine the ploidy of HT22 cells for your research purposes, you may consider performing karyotyping or flow cytometry analysis. These techniques can provide information about the chromosome number and ploidy status of the cell line. Alternatively, you could contact the repository or laboratory from which the HT22 cells were obtained, as they may have additional information about the cell line's ploidy.