diff --git a/tex/thesis.tex b/tex/thesis.tex index b49f08a..60eb282 100644 --- a/tex/thesis.tex +++ b/tex/thesis.tex @@ -1613,6 +1613,8 @@ observing the CD4+ and CD8+ fractions of the naïve/memory subset (\ptmem{}) (\cref{fig:dms_exp_mem4,fig:dms_exp_mem8}). % FIGURE this figure has weird proportions +% FIGURE this figure was not produced with the same donors as the figure above, +% which is really confusing \begin{figure*}[ht!] \begingroup @@ -1740,27 +1742,6 @@ for bead (\cref{fig:car_bcma_total}). \subsection{DMSs efficiently expand T cells in Grex bioreactors} -% RESULT update this in light of the grex data -We also asked if the \gls{dms} platform could expand T cells in a static -bioreactor such a Grex. We incubated T cells in a Grex analogously to that for -plates and found that T cells in Grex bioreactors expanded as efficiently as -bead over \SI{14}{\day} and had similar viability -(\cref{fig:grex_results_fc,fig:grex_results_viability}). Furthermore, consistent -with past results, \glspl{dms}-expanded T cells had higher \pthp{} compared to -beads, but only had slightly higher \ptmemp{} compared to beads -(\cref{fig:grex_mem,fig:grex_cd4}). - -% DISCUSSION is this discussion stuff? -These discrepancies might be explained in light of our other data as follows. -The Grex bioreactor has higher media capacity relative to its surface area, and -we did not move the T cells to a larger bioreactor as they grew in contrast with -our plate cultures. This means that the cells had higher growth area -constraints, which may have nullified any advantage to the expansion that we -seen elsewhere (\cref{fig:dms_exp_fold_change}). Furthermore, the higher growth -area could mean higher signaling and higher differentiation rate to effector T -cells, which was why the \ptmemp{} was so low compared to other data -(\cref{fig:dms_phenotype_mem}). - \begin{figure*}[ht!] \begingroup @@ -1783,12 +1764,25 @@ cells, which was why the \ptmemp{} was so low compared to other data \label{fig:grex_results} \end{figure*} -We also quantified the cytokines released during the Grex expansion using -Luminex. We noted that in nearly all cases, the \gls{dms}-expanded T cells -released higher concentrations of cytokines compared to beads -(\cref{fig:grex_luminex}). This included higher concentrations of -pro-inflammatory cytokines such as GM-CSF, \gls{ifng}, and \gls{tnfa}. This -demonstrates that \gls{dms} could lead to more robust activation and fitness. +We also asked if the \gls{dms} platform could expand T cells in a static +bioreactor such a Grex. We incubated T cells in a Grex analogously to that for +plates and found that T cells in Grex bioreactors expanded as efficiently as +bead over \SI{14}{\day} and had similar viability +(\cref{fig:grex_results_fc,fig:grex_results_viability}). Furthermore, consistent +with past results, \glspl{dms}-expanded T cells had higher \pthp{} compared to +beads and higher \ptmemp{} compared to beads (\cref{fig:grex_mem,fig:grex_cd4}). +Overall the \ptmemp{} was much lower than that seen from cultures grown in +tissue-treated plates (\cref{fig:dms_phenotype_mem}). + +These discrepancies might be explained in light of our other data as follows. +The Grex bioreactor has higher media capacity relative to its surface area, and +we did not move the T cells to a larger bioreactor as they grew in contrast with +our plate cultures. This means that the cells had higher growth area +constraints, which may have nullified any advantage to the expansion that we +seen elsewhere (\cref{fig:dms_exp_fold_change}). Furthermore, the higher growth +area could mean higher signaling and higher differentiation rate to effector T +cells, which was why the \ptmemp{} was so low compared to other data +(\cref{fig:dms_phenotype_mem}). \begin{figure*}[ht!] \begingroup @@ -1801,15 +1795,19 @@ demonstrates that \gls{dms} could lead to more robust activation and fitness. \label{fig:grex_luminex} \end{figure*} -\subsection{DMSs do not leave antibodies attached to cell product} +We also quantified the cytokines released during the Grex expansion using +Luminex. We noted that in nearly all cases, the \gls{dms}-expanded T cells +released higher concentrations of cytokines compared to beads +(\cref{fig:grex_luminex}). This included higher concentrations of +pro-inflammatory cytokines such as GM-CSF, \gls{ifng}, and \gls{tnfa}. This +demonstrates that \gls{dms} could lead to more robust activation and fitness. -We asked if \glspl{mab} from the \glspl{dms} detached from the \gls{dms} surface -and could be detected on the final T cell product. This test is important for -clinical translation as any residual \glspl{mab} on T cells injected into the -patient could elicit an undesirable \antim{\gls{igg}} immune response. We did -not detect the presence of either \ahcd{3} or \ahcd{28} \glspl{mab} (both of -which were \gls{igg}) on the final T cell product after \SI{14}{\day} of -expansion (\cref{fig:nonstick}). +Taken together, these data suggest that \gls{dms} also lead to robust expansion +in Grex bioreactors, although more optimization may be necessary to maximize the +media feed rate and growth area to get comparable results to those seen in +tissue-culture plates. + +\subsection{DMSs do not leave antibodies attached to cell product} \begin{figure*}[ht!] \begingroup @@ -1825,10 +1823,19 @@ expansion (\cref{fig:nonstick}). \label{fig:nonstick} \end{figure*} +% DISCUSSION alude to this figure +We asked if \glspl{mab} from the \glspl{dms} detached from the \gls{dms} surface +and could be detected on the final T cell product. This test is important for +clinical translation as any residual \glspl{mab} on T cells injected into the +patient could elicit an undesirable \antim{\gls{igg}} immune response. We did +not detect the presence of either \ahcd{3} or \ahcd{28} \glspl{mab} (both of +which were \gls{igg}) on the final T cell product after \SI{14}{\day} of +expansion (\cref{fig:nonstick}). + \subsection{DMSs consistently outperform bead-based expansion compared to beads in a variety of conditions} -n order to establish the robustness of our method, we combined all experiments +In order to establish the robustness of our method, we combined all experiments performed in our lab using beads or \glspl{dms} and combined them into one dataset. Since each experiment was performed using slightly different process conditions, we hypothesized that performing causal inference on such a dataset @@ -1877,41 +1884,6 @@ longitudinally, so we included a boolean categorical to represented this modification as removing conditioned media as the cell are expanding could disrupt signaling pathways. -% TODO the real reason we log-transformed was because box-cox and residual plots -We first asked what the effect of each of our treatment parameters was on the -responses of interest, which were fold change of the cells, the \ptmemp{}, and -\dpthp{} (the shift in \pthp{} at day 14 compared to the initial \pthp{}). We -performed a linear regression using activation method and bioreactor as -predictors (the only treatments that were shown to be balanced) -(\cref{tab:ci_treat}). Note that fold change was log transformed to reflect the -exponential nature of T cell growth. We observe that the treatments are -significant in all cases except for the \dpthp{}; however, we also observe that -relatively little of the variability is explained by these simple models ($R^2$ -between 0.17 and 0.44). - -% RESULT add the regression diagnostics to this -We then included all covariates and unbalanced treatment parameters and -performed linear regression again -(\cref{tab:ci_controlled,fig:metaanalysis_fx}). We observe that after -controlling for additional noise, the models explained much more variability -($R^2$ between 0.76 and 0.87) and had relatively constant variance and small -deviations for normality as per the assumptions of regression analysis {Figure - X}. Furthermore, the coefficient for activation method in the case of fold -change changed very little but still remained quite high (note the -log-transformation) with \SI{143}{\percent} increase in fold change compared to -beads. Furthermore, the coefficient for \ptmemp{} dropped to about -\SI{2.7}{\percent} different and almost became non-significant at $\upalpha$ = -0.05, and the \dpthp{} response increased to almost a \SI{9}{\percent} difference -and became highly significant. Looking at the bioreactor treatment, we see that -using the bioreactor in the case of fold change and \ptmemp{} is actually harmful -to the response, while at the same time it seems to increase the \dpthp{} -response. We should note that this parameter merely represents whether or not -the choice was made experimentally to use a bioreactor or not; it does not -indicate why the bioreactor helped or hurt a certain response. For example, -using a Grex entails changing the cell surface and feeding strategy for the T -cells, and any one of these ‘mediating variables’ might actually be the cause of -the responses. - % TABLE these tables have extra crap in them that I don't need to show \begin{table}[!h] \centering \caption{Causal Inference on treatment variables only} @@ -1948,6 +1920,41 @@ the responses. \label{fig:metaanalysis_fx} \end{figure*} +% TODO the real reason we log-transformed was because box-cox and residual plots +We first asked what the effect of each of our treatment parameters was on the +responses of interest, which were fold change of the cells, the \ptmemp{}, and +\dpthp{} (the shift in \pthp{} at day 14 compared to the initial \pthp{}). We +performed a linear regression using activation method and bioreactor as +predictors (the only treatments that were shown to be balanced) +(\cref{tab:ci_treat}). Note that fold change was log transformed to reflect the +exponential nature of T cell growth. We observe that the treatments are +significant in all cases except for the \dpthp{}; however, we also observe that +relatively little of the variability is explained by these simple models ($R^2$ +between 0.17 and 0.44). + +% RESULT add the regression diagnostics to this +We then included all covariates and unbalanced treatment parameters and +performed linear regression again +(\cref{tab:ci_controlled,fig:metaanalysis_fx}). We observe that after +controlling for additional noise, the models explained much more variability +($R^2$ between 0.76 and 0.87) and had relatively constant variance and small +deviations for normality as per the assumptions of regression analysis {Figure + X}. Furthermore, the coefficient for activation method in the case of fold +change changed very little but still remained quite high (note the +log-transformation) with \SI{143}{\percent} increase in fold change compared to +beads. Furthermore, the coefficient for \ptmemp{} dropped to about +\SI{2.7}{\percent} different and almost became non-significant at $\upalpha$ = +0.05, and the \dpthp{} response increased to almost a \SI{9}{\percent} difference +and became highly significant. Looking at the bioreactor treatment, we see that +using the bioreactor in the case of fold change and \ptmemp{} is actually harmful +to the response, while at the same time it seems to increase the \dpthp{} +response. We should note that this parameter merely represents whether or not +the choice was made experimentally to use a bioreactor or not; it does not +indicate why the bioreactor helped or hurt a certain response. For example, +using a Grex entails changing the cell surface and feeding strategy for the T +cells, and any one of these ‘mediating variables’ might actually be the cause of +the responses. + \section{discussion} % DISCUSSION this is fluffy @@ -2390,6 +2397,7 @@ T cells in the \gls{dms} system may need less or no \gls{il2} if this hypothesis were true. % FIGURE this plots proportions look dumb +% FIGURE take out the NLS lines since I don't feel like defending them \begin{figure*}[ht!] \begingroup @@ -2413,7 +2421,6 @@ were true. \label{fig:il2_mod} \end{figure*} -% RESULT the nls stuff is a bit iffy We varied the concentration of \gls{il2} from \SIrange{0}{100}{\IU\per\ml} and expanded T cells as described in \cref{sec:tcellculture}. T cells grown with either method expanded robustly as \gls{il2} concentration was increased @@ -2421,10 +2428,12 @@ either method expanded robustly as \gls{il2} concentration was increased group expanded at all with \SI{0}{\IU\per\ml} \gls{il2}. When examining the endpoint fold change after \SI{14}{\day}, we observe that the difference between the bead and \gls{dms} appears to be greater at lower \gls{il2} concentrations -(\cref{fig:il2_mod_total}). This is further supported by fitting a non-linear -least squares equation to the data following a hyperbolic curve (which should be -a plausible model given that this curve describes receptor-ligand kinetics, -which we can assume \gls{il2} to follow). Furthermore, the same trend can be +(\cref{fig:il2_mod_total}). +% This is further supported by fitting a non-linear +% least squares equation to the data following a hyperbolic curve (which should be +% a plausible model given that this curve describes receptor-ligand kinetics, +% which we can assume \gls{il2} to follow). +Furthermore, the same trend can be seen when only examining the \ptmem{} cell expansion at day 14 (\cref{fig:il2_mod_mem}). In this case, the \ptmemp{} of the T cells seemed to be relatively close at higher \gls{il2} concentrations, but separated further at @@ -2436,11 +2445,11 @@ advantage at lower \gls{il2} concentrations compared to beads. For this reason, we decided to investigate the lower range of \gls{il2} concentrations starting at \SI{10}{\IU\per\ml} throughout the remainder of this aim. -% TODO this is not consistent with the next section since the responses are +% RESULT this is not consistent with the next section since the responses are % different \subsection{DOE shows optimal conditions for expanded potent T cells} -% RESULT not all of these were actually used, explain why by either adding columns +% TABLE not all of these were actually used, explain why by either adding columns % or marking with an asterisk \begin{table}[!h] \centering \caption{DOE Runs} @@ -2465,13 +2474,20 @@ at \SI{10}{\IU\per\ml} throughout the remainder of this aim. \label{fig:doe_response_first} \end{figure*} +% RESULT maybe add regression tables to this, although it doesn't really matter +% since we end up doing regression on the full thing later anyways. We conducted two consecutive \glspl{doe} to optimize the \pth{} and \ptmem{} responses for the \gls{dms} system. In the first \gls{doe} we, tested \pilII{} in the range of \SIrange{10}{30}{\IU\per\ml}, \pdms{} in the range of \SIrange{500}{2500}{\dms\per\ml}, and \pmab{} in the range of -\SIrange{60}{100}{\percent}. +\SIrange{60}{100}{\percent}. When looking at the total \ptmemp{} output, we +observed that \pilII{} showed a positive linear trend with the \pdms{} and +\pmab{} showing possible second-order effects with maximums and minimums at the +intermediate level (\cref{fig:doe_response_first_mem}). In the case of \pth{}, +we observed that all parameters seemed to have a positive linear response, with +\pilII{} and \pdms{} showing slight second order effects that suggest a maximum +might exist at a higher value for each. -% RESULT explain why not all runs were used After performing the first \gls{doe} we augmented the original design matrix with an \gls{adoe} which was built with three goals in mind. Firstly we wished to validate the first \gls{doe} by assessing the strength and responses of each @@ -2485,7 +2501,11 @@ increased the \pilII{} to include \SI{40}{\IU\per\ml} and the \pdms{} to \SI{3500}{\dms\per\ml}. Note that it was impossible to go beyond \SI{100}{\percent} for the \pmab{}, so runs were positioned for this parameter with validation and confidence improvements in mind. The runs for each \gls{doe} -were shown in \cref{tab:doe_runs}. +were shown in \cref{tab:doe_runs}\footnote{Not all runs in this table were used. +It was determined later that the total \glspl{mab} surface density may not be +consistent across each batch of \gls{dms} used, primarily due to the fact that a +subset were created at different scale and with a different operator. To remove +this bias in our data, these runs were not used.}. \begin{figure*}[ht!] \begingroup @@ -2947,21 +2967,20 @@ To block soluble \gls{il15}, we supplemented analogously with \subsection{adding or removing DMSs alters expansion and phenotype} -% RESULT state what collagenase actually targets We hypothesized that adding or removing \gls{dms} in the middle of an active culture would alter the activation signal and hence the growth trajectory and phenotype of T cells. While adding \glspl{dms} was simple, the easiest way to remove \glspl{dms} was to use enzymatic digestion. Collagenase is an enzyme that -specifically targets the blabla domain on collagen. Since our \glspl{dms} are -composed of porcine-derived collagen, this enzyme should target the \gls{dms} -while sparing the cells. We tested this specific hypothesis using either -\gls{colb}, \gls{cold} or \gls{hbss}, and stained the cells using a typical -marker panel to assess if any of the markers were cleaved off by the enzyme -which would bias our final readout. We observed that the marker histograms in -the \gls{cold} group were similar to that of the buffer group, while the -\gls{colb} group visibly lowered CD62L and CD4, indicating partial -enzymatic cleavage (\cref{fig:collagenase_fx}). Based on this result, we used -\gls{cold} moving forward. +specifically targets collagen proteins. Since our \glspl{dms} are composed of +porcine-derived collagen, this enzyme should target the \gls{dms} while sparing +the cells along with any markers we wish to analyze. We tested this specific +hypothesis using either \gls{colb}, \gls{cold} or \gls{hbss}, and stained the +cells using a typical marker panel to assess if any of the markers were cleaved +off by the enzyme which would bias our final readout. We observed that the +marker histograms in the \gls{cold} group were similar to that of the buffer +group, while the \gls{colb} group visibly lowered CD62L and CD4, indicating +partial enzymatic cleavage (\cref{fig:collagenase_fx}). Based on this result, we +used \gls{cold} moving forward. % FIGURE this figure is tall and skinny like me \begin{figure*}[ht!] @@ -3224,6 +3243,7 @@ samples, simply lining up their histograms showed no difference between any of the markers, and by extension showing no difference in phenotype (\cref{fig:il15_1_mem}). +% FIGURE this should say ug not mg \begin{figure*}[ht!] \begingroup @@ -3248,9 +3268,12 @@ the markers, and by extension showing no difference in phenotype \end{figure*} We next tried blocking soluble \gls{il15} itself using either a \gls{mab} or an -\gls{igg} isotype control. Similarly, we observed no difference between fold -change, viability, or marker histograms between any of these markers, showing -that blocking \gls{il15} led to no difference in growth or phenotype. +\gls{igg} isotype control. \anti{\gls{il15}} or \gls{igg} isotype control was +added at \SI{5}{\ug\per\ml}, which according to \cref{fig:doe_luminex} was in +excess of the \gls{il15} concentration seen in past experiments by over 20000X. +Similarly, we observed no difference between fold change, viability, or marker +histograms between any of these markers, showing that blocking \gls{il15} led to +no difference in growth or phenotype. % RESULT this can probably be worded more specifically in terms of the cis/trans % action of IL15 @@ -3626,9 +3649,10 @@ other groups in regard to the final tumor burden. \label{fig:mouse_timecourse_ivis} \end{figure*} -% RESULT this figure -% DISCUSSION this figure +\section{discussion} +% FIGURE add CD45RA to this to rule out one of the alternative possibilities +% explaining this data \begin{figure*}[ht!] \begingroup @@ -3647,9 +3671,10 @@ other groups in regard to the final tumor burden. \label{fig:mouse_summary} \end{figure*} -\section{discussion} +The total number of T cells for each \invivo{} experiment are shown in +\cref{fig:mouse_summary}. -When we tested bead and DMS expanded \gls{car} T cells, we also found that the +When we tested bead and DMS expanded \gls{car} T cells, we found that the \gls{dms} expanded CAR-T cells outperformed bead groups in prolonging survival of Nalm-6 tumor challenged (intravenously injected) \gls{nsg} mice. DMS expanded CAR-T cells were very effective in clearing tumor cells as early as 7 days post @@ -3663,21 +3688,46 @@ results suggest that the higher proportion of memory T cells in DMS groups efficiently kill tumor cells as recently reported in literature\cite{Fraietta2018, Sommermeyer2015}. -% DISCUSSION try and find literature explaining what the ideal ratio is +% DISCUSSION cite a bunch of data saying memory and CD4 T cells are better in +% mice +When comparing the total number of T cells of different phenotypes, we observed +that when comparing low-dose \gls{dms} group to the mid- bead groups (which had +similar numbers of \gls{car} T cells), the number of \ptmem{} T cells injected +was much lower in the \gls{dms} group (\cref{fig:mouse_summary_1}). This could +mean several things. First, the \ptmem{} phenotype may have nothing to do with +the results seen here, at least in this model. Second, the distribution of +\gls{car} T cells across different subtypes of T cells was different between the +\gls{dms} and bead groups (with possibly higher correlation of \gls{car} +expression and the \ptmem{} phenotype). Third, the \ptmem{} phenotype may not be +precise enough, and the functional `memory' phenotype is a subset of \ptmem{} +which may be higher in the \gls{dms} group and explains the discrepancy between +the two methods. + +% DISCUSSION cite why CD4 or CD8 matters in this model +We can also make a similar observation for the number of \pth{} T cells injected +(\cref{fig:mouse_summary_1}). In this case, either the \pth{} phenotype doesn't +matter in this model (or the \ptk{} population matters much more), or the +distribution of \gls{car} is different between CD4 and CD8 T cells in a manner +that favors the \gls{dms} group. + When testing \gls{car} T cells at earlier timepoints relative to day 14 as used in the first \invivo{} experiment, we noted that none of the \gls{car} treatments seemed to work as well as they did in the first experiment. However, -at day 14, we should note that the number of \gls{car} T cells injected in the -second experiment was lower than the lowest dose in the first for both bead and -\gls{dms} (\cref{fig:mouse_timecourse_qc_car,tab:mouse_dosing_results}). While -the \ptmemp{} generally increases with earlier timepoints in the second -experiment, the first experiment suggests that \ptmemp{} may not be the primary -driver in this particular model -(\cref{fig:mouse_timecourse_qc_mem,fig:mouse_dosing_qc_mem}). As with the first -experiment, the \pthp{} seems to be higher overall in the \gls{dms} group than -the bead group (\cref{fig:mouse_dosing_qc_cd4,fig:mouse_timecourse_qc_cd4}), and -this may explain the modest advantage that the \gls{dms} T cells seemed to have -in the second experiment in slowing the progression of tumor burden. +the total number of \gls{car} T cells was generally much lower in this second +experiment relative to the first (\cref{fig:mouse_summary}). Only the day 6 +group had \gls{car} T cell numbers comparable to the weakest dose of bead cells +given in the first experiment, and these T cells were harvested at earlier +timepoints than the first mouse experiment and thus may not be safely +comparable. The lower overall \gls{car} doses may explain why at best, the tumor +seemed to be in remission only temporarily. Even so, the \gls{dms} group seemed +to perform better at day 6 as it held off the tumor longer, and also slowed the +tumor progression relative to the bead group at day 14 +(\cref{fig:mouse_timecourse_ivis_plots}). + +Taken together, these data suggest that on average, the \gls{dms} platform +produces T cells that have an advantage \invivo{} over beads. While we may not +know the exact mechanism, our data suggests that the responses are +unsurprisingly influenced by the \ptcarp{} of the final product. \chapter{conclusions and future work}\label{conclusions}