diff --git a/tex/thesis.tex b/tex/thesis.tex index 2ccec6e..b49f08a 100644 --- a/tex/thesis.tex +++ b/tex/thesis.tex @@ -1390,7 +1390,7 @@ model, the \gls{mab} binding reaction should be complete within \SI{15}{\minute} under the conditions used for our protocol (\cref{fig:dms_mab_per_time}). Note that our unoptimized coated steps were done in \SI{45}{\minute}, which seemed reasonable given the slightly larger hydrodynamic radius of \glspl{mab} compared -to \gls{stp} which was shown to react in \SI{30}{\minutes} experimentally. The +to \gls{stp} which was shown to react in \SI{30}{\minute} experimentally. The results of this model should be experimentally verified. % TODO find the actual numbers for this @@ -1415,21 +1415,6 @@ far less severe than that of \gls{snb}. \subsection{DMSs can efficiently expand T cells compared to beads} -% RESULT add other subfigures here -We next sought to determine how our \glspl{dms} could expand T cells compared to -state-of-the-art methods used in industry. All bead expansions were performed as -per the manufacturer’s protocol, with the exception that the starting cell -densities were matched between the beads and carriers to -~\SI{2.5e6}{\cell\per\ml}. Throughout the culture we observed that T cells in -\gls{dms} culture grew in tight clumps on the surface of the \glspl{dms} as well -as inside the pores of the \glspl{dms} -(\cref{fig:dms_cells_phase,fig:dms_cells_fluor}). Furthermore, we observed that -the \glspl{dms} conferred greater expansion compared to traditional beads, and -significantly greater expansion after \SI{12}{\day} of culture {Figure X}. We -also observed no T cell expansion using \glspl{dms} coated with an isotype -control mAb compared to \glspl{dms} coated with \acd{3}/\acd{28} \glspl{mab} -{Figure X}, confirming specificity of the expansion method. - % FIGURE make sure the day on these is correct \begin{figure*}[ht!] \begingroup @@ -1450,7 +1435,6 @@ control mAb compared to \glspl{dms} coated with \acd{3}/\acd{28} \glspl{mab} \label{fig:dms_cells} \end{figure*} -% RESULT for this figure \begin{figure*}[ht!] \begingroup @@ -1470,26 +1454,23 @@ control mAb compared to \glspl{dms} coated with \acd{3}/\acd{28} \glspl{mab} \label{fig:dms_expansion} \end{figure*} -% RESULT talk about this table somewhere -\begin{table}[!h] \centering - \caption{Regression for fraction of cells in \gls{dms} at day 14} - \label{tab:inside_regression} - \input{../tables/inside_fraction_regression.tex} -\end{table} - -% RESULT state the CI of what are inside the carriers -We also asked how many cells were inside the \glspl{dms} vs. free-floating in -suspension and/or loosely attached to the surface. We qualitatively verified the -presence of cells inside the \glspl{dms} using a \gls{mtt} stain to opaquely -mark cells and enable visualization on a brightfield microscope -(\cref{fig:dms_inside_bf}). After seeding \glspl{dms} at different densities and -expanding for \SI{14}{\day}, we filtered the \glspl{dms} out of the cell -suspension and digested them using dispase to free any cells attached on the -inner surface. We observed that approximately \SI{15}{\percent} of the total -cells after \SI{14}{\day} were on the interior surface of the \glspl{dms} -(\cref{fig:dms_inside_regression}). - -%, and this did not significantly change with initial seeding density (Supplemental Table 1). +% DISCUSSION krish seems concerned about this isotype control figure, add some +% discussion saying that IL2 does not spontaneously activate T cells to appease +% him +We next sought to determine how our \glspl{dms} could expand T cells compared to +state-of-the-art methods used in industry. All bead expansions were performed as +per the manufacturer’s protocol, with the exception that the starting cell +densities were matched between the beads and carriers to +~\SI{2.5e6}{\cell\per\ml}. Throughout the culture we observed that T cells in +\gls{dms} culture grew in tight clumps on the surface of the \glspl{dms} as well +as inside the pores of the \glspl{dms} +(\cref{fig:dms_cells_phase,fig:dms_cells_fluor}). Furthermore, we observed that +the \glspl{dms} conferred greater expansion compared to traditional beads, and +significantly greater expansion after \SI{12}{\day} of culture +(\cref{fig:dms_expansion_bead}). We also observed no T cell expansion using +\glspl{dms} coated with an isotype control mAb compared to \glspl{dms} coated +with \acd{3}/\acd{28} \glspl{mab} (\cref{fig:dms_expansion_isotype}), confirming +specificity of the expansion method. \begin{figure*}[ht!] \begingroup @@ -1509,11 +1490,34 @@ cells after \SI{14}{\day} were on the interior surface of the \glspl{dms} CellEvent dye.} \subcap{fig:apoptosis_bcl2}{Quantification of BCL-2 expression using \gls{elisa}. All statistical tests shown are two-tailed homoschodastic - t-tests.} + t-tests. All cells were harvested at day 8.} } - \label{fig:dms_flowchart} + \label{fig:dms_apoptosis} \end{figure*} +Given that the \gls{dms} system seemed to expand T cells more effectively, we +asked if this difference was due to a reduction in apoptosis or an increase in +proliferation rate (or both). We assessed the apoptotic state of T cells grown +using either bead or \gls{dms} harvested on day 8 using \gls{pi} and \gls{anv}. +\gls{anv} is a marker which stains phospholipid phosphatidylserine, which is +usually present only on the cytoplasmic surface of the cell membrane, but flips +to the outside when the cell becomes apoptotic. \gls{pi} stains the nucleus of +the cell, but only penetrates necrotic cells which have a perforated cell +membrane. When staining for these two markers and assessing via flow cytometry, +we observe that the \gls{dms}-expanded T cells have lower frequencies of +apoptotic and necrotic cells (\cref{fig:apoptosis_annV}). Furthermore, we +stained our cultures with CellEvent dye, which is an indicator of \gls{cas37}, +which is activated in apoptotic cells {\#}{cas37 activation}. In line with the +\gls{pi}/\gls{anv} results, we observed that the \gls{dms} T cells had lower +frequency of \gls{cas37} expression, indicating less apoptosis for our method +(\cref{fig:apoptosis_cas}). Finally, we lysed our cells and stained for +\gls{bcl2}, which is also upregulated in apoptosis. In this case, some (but not +all) of the bead-expanded cultures showed higher \gls{bcl2} expression, which +could indicate more apoptosis in those groups (\cref{fig:apoptosis_bcl2}). None +of the \gls{dms} cultures showed similar heightened expression. Taken together, +these data suggest that the \gls{dms} platform at least in part achieves higher +expansion by lowering apoptosis of the cells in culture. + % FIGURE double check the timing of this experiment (it might not be day 14) \begin{figure*}[ht!] \begingroup @@ -1535,31 +1539,29 @@ cells after \SI{14}{\day} were on the interior surface of the \glspl{dms} \label{fig:dms_inside} \end{figure*} +\begin{table}[!h] \centering + \caption{Regression for fraction of cells in \gls{dms} at day 14} + \label{tab:inside_regression} + \input{../tables/inside_fraction_regression.tex} +\end{table} + +% RESULT state the CI of what are inside the carriers +We also asked how many cells were inside the \glspl{dms} vs. free-floating in +suspension and/or loosely attached to the surface. We qualitatively verified the +presence of cells inside the \glspl{dms} using a \gls{mtt} stain to opaquely +mark cells and enable visualization on a brightfield microscope +(\cref{fig:dms_inside_bf}). After seeding \glspl{dms} at different densities and +expanding for \SI{14}{\day}, we filtered the \glspl{dms} out of the cell +suspension and digested them using dispase to free any cells attached on the +inner surface. We observed that approximately \SI{15}{\percent} of the total +cells after \SI{14}{\day} were on the interior surface of the \glspl{dms} +(\cref{fig:dms_inside_regression,tab:inside_regression}). Performing linear +regression on this data revealed that the percentage of T cells inside the +\glspl{dms} does not depend on the initial starting cell density (at least when +harvested after \SI{14}{\day}) (\cref{tab:inside_regression}). + \subsection{DMSs lead to greater expansion and memory and CD4+ phenotypes} -After observing differences in expansion, we further hypothesized that the -\gls{dms} cultures could lead to a different T cell phenotype. In particular, we -were interested in the formation of naïve and memory T cells, as these represent -a subset with higher replicative potential and therefore improved clinical -prognosis\cite{Gattinoni2011, Wang2018}. We measured naïve and memory T cell -frequency staining for CCR7 and CD62L (both of which are present on lower -differentiated T cells such as naïve, central memory, and stem memory -cells\cite{Gattinoni2012}). Using three donors, we noted again \glspl{dms} -produced more T cells over a \SI{14}{\day} expansion than beads, with -significant differences in number appearing as early after \SI{5}{\day} -(\cref{fig:dms_exp_fold_change}). Furthermore, we noted that \glspl{dms} -produced more memory/naïve cells after \SI{14}{\day} when compared to beads for -all donors (\cref{fig:dms_exp_mem,fig:dms_exp_cd4}) showing that the \gls{dms} -platform is able to selectively expand potent, early differentiation T cells. - -Of additional interest was the preservation of the CD4+ compartment. In healthy -donor samples (such as those used here), the typical CD4:CD8 ratio is 2:1. We -noted that \glspl{dms} produced more CD4+ T cells than bead cultures as well as -naïve/memory, showing that the \gls{dms} platform can selectively expand CD4 T -cells to a greater degree than beads (Figure 2c). The trends held true when -observing the CD4+ and CD8+ fractions of the naïve/memory subset (CD62L+CCR7+) -(\cref{fig:dms_exp_mem4,fig:dms_exp_mem8}). - \begin{figure*}[ht!] \begingroup @@ -1587,7 +1589,28 @@ observing the CD4+ and CD8+ fractions of the naïve/memory subset (CD62L+CCR7+) \label{fig:dms_exp} \end{figure*} -% RESULT add a paragraph for this figure +After observing differences in expansion, we further hypothesized that the +\gls{dms} cultures could lead to a different T cell phenotype. In particular, we +were interested in the formation of naïve and memory T cells, as these represent +a subset with higher replicative potential and therefore improved clinical +prognosis\cite{Gattinoni2011, Wang2018}. We measured naïve and memory T cell +frequency staining for CCR7 and CD62L (both of which are present on lower +differentiated T cells such as naïve, central memory, and stem memory +cells\cite{Gattinoni2012}). Using three donors, we noted again \glspl{dms} +produced more T cells over a \SI{14}{\day} expansion than beads, with +significant differences in number appearing as early after \SI{5}{\day} +(\cref{fig:dms_exp_fold_change}). Furthermore, we noted that \glspl{dms} +produced more memory/naïve cells after \SI{14}{\day} when compared to beads for +all donors (\cref{fig:dms_exp_mem,fig:dms_exp_cd4}) showing that the \gls{dms} +platform is able to selectively expand potent, early differentiation T cells. + +Of additional interest was the preservation of the CD4+ compartment. In healthy +donor samples (such as those used here), the typical CD4:CD8 ratio is 2:1. We +noted that \glspl{dms} produced more CD4+ T cells than bead cultures as well as +naïve/memory, showing that the \gls{dms} platform can selectively expand CD4 T +cells to a greater degree than beads (Figure 2c). The trends held true when +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 \begin{figure*}[ht!] @@ -1608,6 +1631,25 @@ observing the CD4+ and CD8+ fractions of the naïve/memory subset (CD62L+CCR7+) \label{fig:dms_phenotype} \end{figure*} +We also observed that, at least with the donors and conditions tested in these +experiments\footnote{these results were not always consistent, see the + metaanalysis at the end of this aim for an in-depth quantification of this + observation} that the fraction of \ptmem{} and \pth{} T cells was higher in +the \gls{dms} groups compared to the bead groups (\cref{fig:dms_phenotype}). +This result was seen for multiple donors. We should not that in the case of +\pthp{}, the donors we used had an initial \pthp{} that was much higher (healthy +donors generally have a CD4:CD8 ratio of 2:1), so the proper interpretation of +this is that the \pthp{} decreases less over the culture period with the +\gls{dms} platform as opposed to the beads (or alternatively, the \gls{dms} has +less preferential expansion for CD8 T cells). We cannot say the same about +the \ptmemp{} since we did not have the initial data for this phenotype; +however (although it should be the vast majority of cells given that +cryopreserved T cells from a healthy donor should generally be composed of +circulated memory and naive T cells). Taken together, these data indicate the +\gls{dms} platform has the capacity to expand higher numbers and percentages of +highly potent \ptmem{} and \pth{} T cells compared to state-of-the-art bead +technology. + \subsection*{DMSs can be used to produce functional CAR T cells} After optimizing for naïve/memory and CD4 yield, we sought to determine if the @@ -3077,8 +3119,6 @@ them to grow better in the \gls{dms} system. \label{fig:integrin_1} \end{figure*} -% RESULT alude to these tables - \begin{table}[!h] \centering \caption{Linear regression for day 14 phenotype shown in \cref{fig:integrin_1}} \label{tab:integrin_1_reg} @@ -3092,9 +3132,9 @@ These block \glspl{mab} were added at day 6 of culture when \gls{a2b1} and identical in all the blocked groups vs the unblocked control group (\cref{fig:inegrin_1_fc}). Furthermore, we observed that the \ptmemp{} (total and across the CD4/CD8 compartments) was not significantly different between any -of the groups (\cref{fig:inegrin_1_mem}). We also noted that \gls{a2b1} and -\gls{a2b2} were present on the surface of a significant subset of T cells at day -6, showing that the target we wished to block was present +of the groups (\cref{fig:inegrin_1_mem,tab:integrin_1_reg}). We also noted that +\gls{a2b1} and \gls{a2b2} were present on the surface of a significant subset of +T cells at day 6, showing that the target we wished to block was present (\cref{fig:inegrin_1_cd49}). \begin{figure*}[ht!] @@ -3131,22 +3171,22 @@ its maximum. Once again, we observed no difference between any of the blocked conditions and the unblocked controls in regard to expansion (\cref{fig:inegrin_2_fc}). Furthermore, none of the \ptmemp{} readouts (total, CD4, or CD8) were statistically different between groups -(\cref{fig:inegrin_2_mem}). +(\cref{fig:inegrin_2_mem,tab:integrin_2_reg}). Taken together, these data suggest that the advantage of the \gls{dms} platform is not due to signaling through \gls{a2b1} or \gls{a2b2}. \subsection{blocking IL15 signaling does not alter expansion or phenotype} -% RESULT cite the luminex data \gls{il15} is a cytokine responsible for memory T cell survival and maintenance. Furthermore, we observed in other experiments that it is secreted to a much -greater extend in \gls{dms} compared to bead cultures. One of our driving -hypotheses in designing the \gls{dms} system was that the higher cell density -would lead to greater local signaling. Since we observed higher \ptmemp{} across -many conditions, we hypothesized that \gls{il15} may be responsible for this, -and further that the unique \textit{cis/trans} activity of \gls{il15} may be -more active in the \gls{dms} system due to higher cell density. +greater extend in \gls{dms} compared to bead cultures (\cref{fig:doe_luminex}). +One of our driving hypotheses in designing the \gls{dms} system was that the +higher cell density would lead to greater local signaling. Since we observed +higher \ptmemp{} across many conditions, we hypothesized that \gls{il15} may be +responsible for this, and further that the unique \textit{cis/trans} activity of +\gls{il15} may be more active in the \gls{dms} system due to higher cell +density. \begin{figure*}[ht!] \begingroup